The Librarian should shut them up or kick them out for being disruptive. That's what Librarians do. Keep talking to your Librarian if the people won't shut up. Don't bother confronting people yourself because you don't have the authority to kick them out of the library and could wind up getting your arse kicked out in the library parking lot.
You must be in the USA.. the libraries I've been to in Canada were all quiet no talking. If you talk too loud the Librarian kicks you out! There are a few libraries that do have a room where you're allowed to talk but that room you're also allowed to try CDs or DVDs I haven't come across any rude people in the library! I go often too!
People are rude everywhere these days.
Why not spend the day offline.Just thumb through some books and then go out side and find a nice tree to sit under and read.
Its like that everywhere,people just cant shut up for five minutes. I blame too much sugary drinks and sweets, it gives them the verbal runs.
Maybe they got kicked out of their apartment for a bit and have nowhere to go either?