I'm an AI skeptic, but I don't see how this squares with what the organisers of the event actually say. "It previously suggested that math researchers already have no place in mathematics"? I don't see this.

The website previously said, “What is the role of a mathematician when AI can solve conjectures faster?” but they have removed it, possibly as a result of the letter since it happened after.

Also I want to mention that the letter is not about AI skepticism, in any direct way at least.