The typical advice is "if you want to see more like this, vote up; if you want to see less like this, vote down." Users try to downvote for faulty premises or logic rather than conclusions they disagree with.

For short posts, where claims are made without much justification, there tends to be little besides a conclusion. Those comments will get voted down if they seem wrong or to not add much to the conversation. (I've had several offhand remarks, for which I had solid, non-obvious justification, voted down, but then in responses I made up the karma by explaining myself fully. I suspect that if I had explained myself fully at the start, I wouldn't have gotten downvoted.)