Not so much a snob thing as a necessity thing. Aside from having lots of tunes memorized, I can't think of a jazz gig where being able to read (at least chord charts) wasn't a vital part of the gig. On top of that a solid knowledge of theory plays an important role because one has to sightread some tough changes, and that involves knowing the fretboard very well. That's just how the gig works, like it or not.
Simply put, if a bassist is unwilling to put the time and effort in to learn these thing well, he/she should not expect to see very many jazz gigs in their future until they do. In the meantime there is alot of great music out there to play that doesn't require these things. Sounds very harsh I know, but its reality. A carpenter must cut straight. An accountant must be good at math. An NBA player must be able to shoot well (unless you're Shaq of course). A jazz bassist must have certain tools in his/her bag to play the gig.