Keep in mind that votes aren't supposed to be about whether you agree or disagree, but whether a comment adds substance to the thread. A good question that makes a wrong assumption can be worth upvoting; a correct but fairly irrelevant statement about politics not (to give a relatively obvious example)

Being "voted to -2" doesn't necessarily mean you were wrong (it often correlates though). People might just think it wasn't relevant in whatever context you posted it in

I often find it hard to tell what makes people think something I write is not helpful (or sometimes also a comment someone else made) and thus appreciate comments that clarify constructively. It can also help to ask for clarification if you're particularly surprised about the votes on a given post