Maybe they made a video just for fun? I think there is a little too much analysis going on here. Pork and Beans isn't supposed to be an orchestral masterpiece - apparently front man Rivers was making a stab at his record label (Geffen Records, who he fights with a lot apparently and is pretty much regretting ever signing with them - from what I understand) for rejecting other stuff he had written and trying to mold the band into a mainstream kind of thing.
Weezer has been influential in the "alt-rock scene", been very identifiable with a certain crowd, and in general produced catchy, enjoyable songs. They aren't for destroying your mind with some crazy new acoustics, but something to simply enjoy.
I don't know, just saying.
Also, saying that you love the Blue Album and Pinkerton but hate the "new stuff" doesn't make you smart.