> (I don't think it was very nice of whoever downvoted you, presumably because you're wrong, given you explicitly allowed that you might not be getting it.)

I believe this is how this website works: if someone thinks you are wrong, they will downvote your comment. It's best not to think about in terms of niceness but more about getting the content most people agree with, or considered the most valuable by the majority, to the top so that more people can view and discuss it.