The person you are talking to did not personally commit genocide in Gaza. Just as I, an American citizen, did not declare war on Iran.

In fact, I think the war in Iran is a stupid and immoral thing to do. It's possible that the person you are responding to feels the same about the Israeli government's genocidal actions in Gaza.

However, you did not bother to find out. When you judge someone before knowing them, it is called "prejudice". Pre-judging.