I recently got into blogging; and while I was designing my site, I went through hundreds of blogs and personal sites, and I saw many instances of the same thing.
I would, however, add that just because most people are bad at estimating others doesn't mean that everyone is equally bad. There may be some people who are incredibly good at seeing where others are coming from and what their true intentions are. But, of course, everyone's probably overestimating their own capacity to estimate others.
I wonder if this is because the creators routinely prune negative comments of them. Or perhaps it is because Youtube severely down ranks comments with dislikes.