My mom is a librarian and trust me the loud people are native Americans talking on their cellphones with no regard for the fact that they are in a place where they should probably take their conversations outside. It's a daily battle to try and get people not to announce what they had or will have to for lunch to every one in the place. The common every day conversations aren't event he worst of it, my mom has had to ask people to please talk about the sex they had last night out side, or in the lobby rather then sharing it with every patron in the place. Yes kids are loud in the library, but I think most librarians are ok with that within reason.
To add to this: Modern libraries are one of the few remaining places where you don't get thrown out just for loitering. They're free wifi-enabled, air-conditioned spaces. I worked at one, in an extremely affluent area, for several years. Our problem was, partially, with children, as kleinbl00 says -- though that was mitigated by the partitioning of the children's section -- but overwhelmingly with homeless people who had nowhere else to be. We couldn't throw them out until /after/ they had already disturbed the supposed inherent quiet of the library, and most did, inevitably, because the majority had mental illnesses and no family. I talked to dozens of them. My point with all this is that a large part of kleinbl00's post above is overly general. (Silence is freely available at reading rooms? We had a reading room, even though I was under the impression that libraries really were reading rooms anyway, at my old job -- and people went in their to make calls. What can ya do.) I side with the article on this one.