I don't have to talk *&^% or gossip about people to hate them. I don't find the law school environment to be like high school at all, but I still get f-ing irritated by gunners.
People's ideas about "how to act like a human being" vary, as a rule, and the law school classroom is emphatically not the undergrad classroom (see, e.g., the Socratic method). Things that would be less obnoxious in undergrad can be significantly more obnoxious in law school. One of those things is asking follow-up questions during lecture.
I don't know why you would assume that the class would be interested in your questions. I think that if you err, rather, on the side of "this is interesting solely or at least primarily to me," you probably are on the right track. And if that's your default position, then you're much less likely to talk-to-hear-yourself-talk, which is the true mark of gunnerdom (the gunner presumably doesn't see it that way--at least, one would hope--but that's inevitably how it comes across).