He's not really vilified at all anymore (other than for signing a bunch of shitty bands to Epitaph), but Greg left the band shortly after this album on less-than-amicable terms. He formed a band called Daredevils, who released a single titled "Hate You" that was definitely aimed at bassist Jay Bentley.
Brett. Not Greg (either one), and he did in fact admit it was completely about Bentley although like you said it was pretty obvious. They had another song on that single called "Rules, Hearts" too. LOL Gore Verbinski was the second guitarist (yes, the famous director) and Josh Freese was the drummer too!
Digging: United Nations - The Next Four Years