>casting himself as an extremist nut, increasing the resistance to his viewpoint in the population at large.

I think the majority of the population at large either doesn't care about what happened or wish that the guy had actually managed to kill Altman. Not even necessarily because Altman is involved with AI, but just because he is extremely rich. I don't imagine any increased resistance from the population at large - the population at large either doesn't mind when rich people are killed or loves it. The exceptions would be people like entertainers who develop a parasocial relationship with the public and provide direct joy to people, but AI company leaders don't fall into that category.

That said, it is true that killing Altman would almost certainly achieve nothing. See my other post in this thread.