The issue I have with judging is not in assessing the situation. I don't mind someone reviewing my posts and then judging me to be someone who supports gay rights. The problem is judging someone as inferior or wrong based on doing something you dislike, and using your position as judge to assert superiority over the situation. Also, judging the situation or action (such as homosexuality, that being a big thing) is different then judging the person. That's forgotten in many situations.
As far as a post over people being evil, I don't think anyone can be 100% evil. They can do terrible, dangerous things, they can commit a series of shocking crimes. Judging them on the basis of the crime is fine, asserting that they are wicked because of the action, with no positive qualities whatsoever is dangerous. Especially in the case of judging the sin not the sinner, so many people claim to hate only the sinful action, but then turn around posting generalizing things such as "those homosexuals". Judging the action would no allow for reducing the people to one aspect of their sex lives.