From your post, they come across as being somehow moronic, as you would think of them yourself, which raises the question: why are you friends with such people on Facebook if you don't want to have to talk to them?
The only people on my Facebook who even remotely resemble such awful grammar, spelling, and this 'all-caps-out' approach to discussions are girls who keep only to posting on their own walls and between them.
Personally, I tolerate Facebook chat, for having a quick discussion, or notifying someone about something in private without having to go for wall posts. Then again, I keep to using Steam to talk to friends online, and as I said before, my Facebook friends don't do that sort of thing.