Weird source, they absolutely identified the person, and it was Abu Sitta. He was the reason the conference had to be stopped.
edit.: I’ve looked for a somewhat decent German source to share and found something interesting. The Palestine conference was banned because a speaker named Abu Sitta wanted to hold a speech, who is banned from political activity in Germany. This guy is specifically pro Hamas and said, if he was younger he would’ve participated in the Hamas attack himself. At the same time this other person was banned from entry into the country, also named Abu Sitta. I’m now left wondering if this Schengen ban was mistakenly issued and meant for the other guy.