I followed this reasonably closely, and I didn't see anyone in the Math community criticize Atiyah. And Math is certainly pretty pro-speculation.
People were mostly just sad that journalists were hyping up an obvious case of age-related cognitive decline from a brilliant Mathematician.
And to be clear, Atiyah's last work wasn't speculation – it was completely off, in the "not even wrong" category. Unfortunately, that's pretty common as people get older, but there's no reason to publicize it.
i think it is relatively common in creatively brilliant people who become older. some people solve problems in ways that are counterintuitive and against the grain. it takes a lot of courage to do this, especially social courage. so for the few people that have success with this way of thinking, as they get older, they are trying to resummon the processes they've used before. much of that includes not listening to those who tell you you're wrong. but some declination of mental faculties makes this a bit dangerous as the mind isn't as sharp as it once was. although some of it may be even as simple as they miss the attention.
Note to self: Keep a pet-puzzle(s) that is difficult but solvable. As I grow old, keep solving the puzzles to determine how senile I am. No need to believe others assertions at face value.
I seem to recall that another mathematician, John Conway, did something a bit like that: perhaps he had set up his computer to force him to do his "Doomsday" algorithm in his head whenever he logged on, or something like that. I can't remember exactly (perhaps I'm going a bit senile).
It seems to me people were more upset with the conference organizers allowing him to submit the talk knowing he was going senile, though I don't know the full story or whether or not he was going senile.
It is not hard to say that something is wrong. It is not hard to hope that someone so intelligent is allowed to show publicly how his intelligence has gone astray.
