Whether it's a sense of superiority or just to be funny or asinine or out of a genuine need to spread the truth, people online generally try to be contrarian as often as possible because it gives them some sort of personal gratification or a sense that they're correcting something wrong in the universe.
Yes, but not necessarily in a bad way. I enjoy finding small issues which others may not typically notice; half the time they are taken as intended (see: https://lemmy.world/comment/9002659), in a collegial way. I don't intend to be contrarian per se, which I think is at odds with your mention of correcting something "wrong" as you can be contrarian just to annoy rather than because there's an issue.