I'm not saying he should leave those things on the slides and not say them - that would be silly, it's good content. I'm saying that the slides don't have to have the same text. Give either summaries or extra info on them. Pictures are cool too. Just don't stop what you're talking about to look at the screen and read what's written there.

The disability argument doesn't really apply here - what about deaf users, why say anything that's not on the slides? Because that's what the transcript is for. Usability is orthogonal to what I'm saying.