Yes, if you would be nice to your in-group, and mean to a predictable out-group in a snide kind of way that people could laugh along with, you would have a much bigger fanbase. People like to watch their side win arguments and “smackdown” the other side.
I think it’s interesting because people accuse you of being mean, but you are actually nicer than average. David Deutsch wrote really mean emails on TCS list, where he made fun of people and didn’t actually explain the TCS ideas he thought that they were not following, and his fans liked that. They thought he was good and smart and putting people in their place. He would write snide, cryptic emails, and then not even reply to follow up questions, but for some reason people are OK with that.
You actually put effort into having conversations with people who want to talk to you, and are willing to actually have extended conversations where you try to reach conclusions. You put effort into actually explaining your ideas to people, and explaining your disagreements.
Being unwilling to explain disagreements (as the guy in the video was, and as DD was in his emails) is actually a sign that you don’t respect the other person. You don’t expect them to actually be convinced by reason and arguments.
Pointing out disagreements and trying to explain issues is a sign that you actually respect that the person you are talking to has access to thought and reason, and could think about what you are saying and could actually learn and understand your ideas and arguments. But for some reason people just see it as “mean”. They think it would somehow be less mean to be so disrespectful of someone that you never even bother to tell them that you disagree with them, even when they are literally on your forum for the purpose of learning, understanding, or discussing your ideas.