My esteemed former housemate has a post up on the current ideological state of American TV that I thought was worthy of discussion, so go read that first.
Whilst in the most general sense, I have sympathy for an argument that says that the TV deck is stacked in favour of my end of the aisle, I think the actual situation is deeply complex, and merits detailed consideration.
First of all, at the risk of being facetious, I'm not sure 2.5 M is necessarily the best case study for liberal programming. A rich playboy who beds whomever the hell he wants without consequences? That's pretty much the GOP dream. The only difference between Charlie PseudoSheen and Newt Gingrich is that Newt screwed around whilst he was already married. And then ran for President.
Dexter also strikes me as a poor example, because whilst there's certainly a good deal of shagging going on in there, the central concept of a man who decides that the legal system (controlled by the government) needs to be circumvented in favour of individual action is entirely consistent with the views of much of the American right. "Government is never the solution", as Reagan put it.
This, indeed, points to a major problem in determining the ideology of such shows; a live-and-let-live ethos and a rejection of standard authority is at least as indicative and in many ways more indicative of right wing libertarianism than it is of what the Americans would recognise as liberalism (and what, and I'm sure Tomsk will correct me if I'm wrong, I tend to think of as "social liberalism"). One need only look - and I think I've mentioned this before - at the number of US shows that start from the premise that someone can redeem themselves for past crimes according to their own moral compass, rather than that of the state (see, for example, Angel, or (EDIT: Whoops! Forgot to actually add the second example, which I've now forgotten. Damn.)). That's neither a liberal nor a conservative position, so much as a libertarian one.
Moreover, it makes for good TV, in a way that a hero turning himself into the boys in blue doesn't. The idea of "do what thou wilt" is hardwired into an awful lot of American TV, and I'd question whether that stems from liberal leanings so much as the the veneration (I'd would say "fetishisation", but that's both an abuse of language and a topic for another time) of freedom in American culture. In truth, I rather think in recent years American conservatives have become rather contemptuous of a whole host of freedoms, but I feel safe in assuming that this is a point neither Gooder nor FOX is attempting to make.
We should also consider that there's a real risk of selection bias here. The vast majority of British people - including me - who watch American TV shows are watching those that have already been judged impressive (or at least watchable) by some kind of international Western audience, which is of course significantly more liberal (as a general rule) than a great deal of the States. I have some vague recollection - and that's all it is, so take this with a hefty pinch of salt - that a lot of local American TV in the Bible Belt and elsewhere in the South is a lot more socially conservative, and we never get to see it. As I say, I can't back that up at the minute with any specific examples, but it's at least worth bearing in mind when Englishmen discuss the state of American TV.
More importantly, the problem with saying things like "US TV is liberal" is that it fails to note that liberalism can be divided into social and economic arms at the very least, and also -as mentioned already - because liberalism and libertarianism, whilst very different in many respects, both have (or are supposed to have) a live-and-let-live attitude, which I think is what's really on display here. In addition, one needs to consider what a conservative program would even look like in the first place. I can't say what made Gooder choose the examples that he did, but the common theme would seem to be that the "liberal" programmes include things that piss of conservatives, whereas his example of a "conservative" programme, 24 , got liberals hot under the collar. But 24 is an anomalously easy call because it explicitly deals with politics and national security, both of which have (broadly speaking) well established and mutually exclusive liberal and conservative positions.
If we're really going to compartmentalise American TV in general, though , we need a better definition of a conservative show. Is, for example, The Cosby Show conservative? That's all about the importance of family and marriage, two things which American conservatives are convinced liberals don't give a shit about. If a show in which a woman gets an abortion without crippling remorse or long-term psychological problems, then a) is that a liberal show, and b) what's the alternative to make the show conservative? If she chooses to keep the baby, is that conservative (in truth, a lot of liberals argued that this was the case regarding Juno, which if nothing else serves as proof that not everyone I nominally agree with necessarily has two IQ points to rub together)? Or does the show specifically have to show her refusing to even countenance it, or even for her to go through with it with massive negative consequences?
This is where we get to the very meat of the problem. Even at its best, American conservatism, as well as our home-grown version, is as regards its social aspect (there is of course an economic aspect which is just as important; this is another reason why breaking up TV shows into "liberal", "conservative" and "neither" is probably a bad idea) significantly, if not primarily, concerned with the importance of what is "normal". Marriage is "normal". Family is "normal". Being straight, white and heterosexual is "normal". All of which means that shows that fit in with the conservative viewpoint are by their very nature more difficult to spot . I wonder what the black, Hispanic and homosexual communities would think about Gooder's suggestion that Friends is liberal. Six white straight people with more money than sense taking it in turns to sleep with each other? That's not the liberal dream, that Paris Hilton's Saturday afternoons.
We cannot judge a show by how many times it does something contrary to conservative thinking, because so often every time it does something in line with conservative thinking, it passes without comment.
And all of this, all nine of the above paragraphs (hey, well done for making it this far!) is without dealing with the fact that over-representation is not the same thing as bias. There are certainly TV shows (or at least episodes) that do portray certain conservative ideas in a bad light. But that's where studies need to be focused. Not on how different political groups view what is portrayed, but regarding how political groups are portrayed themselves.
(Lastly, and somewhat parenthetically, I'd like to point out that the example of the Simpsons might show something other than what is intended. Far from proving that even FOX feels compelled to show liberal shows, I'd say it merely proves that FOX prefers raking in shitloads of cash to ensuring all it's programmes tow the conservative line. Indeed, the one time I'm aware of FOX giving direct orders to the Simpsons writers, it was that they were never again allowed to make fun of FOX News, after Groening et al portrayed FOX News anchors as being rabid propagandists.)
 Indeed, the argument that US TV is drowning in a sea of liberalism can be easily punctured thus: liberals don't like guns. How many American shows involve people who have are not agents of the state using guns? I can't give a precise value, but I'm estimating that it's a metric fuck ton. And why? Because guns can make a story interesting. Just like divorce and constant bonking.
In fact, I'll make Gooder a deal. Let's go through all the American TV drama episodes we own between us (I'm only including drama because sex is far easier to get laughs out of than gunplay), and count how many of them involve sex outside of marriage, and how many involve a hero or heroine holding a gun despite being neither a cop nor a federal agent. If the ratio ends up being more than 1:10 (a fairly generous one in scientific terms) in favour of between-the-sheets action, I'll buy you dinner.
But not in a gay way. I don't want this argument to have a liberal bias.