Alright. As a diehard punk fan, i have to put in my .02.
I think the reason why many people believe that punk bassists suck is because many of them are guitarists filling in the role of a bassist, or "all they do is pound out 8th notes". There are exceptions to the rule, many exceptions, and punk basslines do seem to be getting more melodic, and you can see that even the "8th note pounders" do have talent- in their fills and creative basslines. In fact, some punk bassists have been spectacular in my opinion (Joe Principe (rise against), Klaus Flouride (dead kennedys, im aware they have been mentioned before). I personally love this style of music, and there is a certain joy to playing it that these gentlemen have found, as have i. I love playing punk, gives me a nice break from playing jazz music with jazz band, and frankly it is a hell of alot of fun to play, to jump and dance around and sometimes just look angry and driven. Or they could play it, in many cases, to get a message out (bad religion, NoFx, Rise Against, Against Me!, the entire fat wreck label, etc)
Oftentimes, they have a message to convey and that far surpasses the need to show off their chops. I agree with that idea. And if the music that you love calls for it, do it.