Too many people have the wrong definition of self-defense in this day and age. They think if you touch them in the wrong way or even just verbally insult them, that gives them the right to kill you.
Kyle Rittenhouse literally had thugs chasing him with weapons. Karmelo Anthony was asked to leave because he was in the wrong tent. Those two things aren't even comparable.
Kyle himself has pointed out how it makes no sense. I'm surprised he's as outspoken as he is, considering what he went through, but it's definitely not unwelcome.