First of all, take Family Guy and Futurama. These are actual semi-successful network sitcoms, and it's on Adult Swim every goddamn day of the week. Adult Swim is always more than willing to show everyone how high the ratings for Futurama and Family Guy are and how that makes them better than all of the original shows combined.
Then there's Home Movies. This was an unsuccesful network sitcom, but a network sitcom nonetheless, which is why Adult Swim will occasionally give it a weekday spot, or a good time slot.
Now we move into the Adult Swim original shows. First of all, there's Harvey Birdman Attorney at Law. If Friends was 12 minutes long, animated, and set in a lawfirm, it would be Harvey Birdman Attorney at Law. And as this show would fit right in on a primetime network slot, Adult Swim will always get fully erect whenever the Birdman creators decide to shit out 33 minutes worth of material a year.
Aqua Teen Hunger Force, pardon my sacriledge, is sitcommy, and that's why Adult Swim cares about it. Now don't get me wrong, I love Aqua Teen Hunger Force, but it is technically a situation comedy. The creator described the show as "Three's Company on acid". Acid or not, Three's Company is a sitcom. That is why Adult Swim cares about ATHF more than the average AS original.
The Brak Show and Sealab 2021 have a little bit of sitcomminess to them, and as such, Adult Swim doesn't totally not care about them, but also doesn't care about them too much. The Brak Show started out as being a sitcom-spoof, but now evolved into just Brak and crew being weird. The creators of Sealab 2021 said that they were looking to make a show like Cheers, with an ensemble cast that takes place in one location.
Space Ghost Coast to Coast, on the other hand, is about as far from a sitcom as you can get, and that's why Adult Swim couldn't give a fuck about it. I mean, look, here's Full House, and all the way on Alpha Centauri is Space Ghost Coast to Coast.
There are some exceptions to this rule. For example, Mission Hill was a network sitcom, and Adult Swim cared about it even less than Space Ghost.
The point of this article was to show you that even the television block that all pretentious assholes love to throw out when they want to prove that they don't watch "normal TV" has pretty much the same standards of comedy as ABC. Chew on that, fuckers.