Meeting participant drew offensive image on speaker's slide

I was hosting an event at the end of Sept that got zoom bombed with a participant drawing on the speaker's slide with an offensive image. In Host Tools, I had turned off all features for particpants except chat. And still someone was able to draw on the slide. I read that the speaker should have turned off annotation for participants, but the speakers didn't realize and I didn't know I had to ask them. I'm lodging a formal complaint that this feature is not part of the Host Tools. It needs to be. I'm canceling our account.