I mainly downvote with 2 criteria in mind: is it offensive language (and no, I don't just mean swearing. I mean is the writer trying to put down someone else for little to no reason in an offensive way) and is it nonsense (nothing to do with either the topic at hand i.e. the chapter or a direct reply to someone commenting on the chapter). If I see the former, I'll almost certainly - them and, if bad enough, possibly report. The latter depends on how out of context it is and whether it made me laugh.