I am not sure if he actually took part in the event, but there were people involved with him that were present who said he might be dropping by and that he had bought a ticket
Note that at this point we only have indirect word that he bought a ticket. Also note that anyone can buy a ticket, and if his ticket was cancelled by Manifold (which is probably the thing you want), we would not hear about that directly. Of course, information can emerge that he actually did attend.
I strongly disagree. I think human extinction would be bad.
Not every utility function is equally desirable. For example, an ASI that maximizes the number of paperclips in the universe would be a bad outcome.
Most people here do adopt anthropocentric values, in that they think human flourishing would be more desirable than a vast amount of paperclips.