Of course it isn't cool, but it's impossible to prevent people from being wrong on the internet. The question is how to correct misinformation when it appears. If you blame people and snark at them, that reinforces them in the error. Worse, you discredit the truth in the eyes of the neutral audience who might be persuadable, but react adversely to the hostility. Your comment upthread was much better, especially because it provided an alternate source.