No question it was Keystone level stuff. BUT...two important things:
Stupid or not, he really did it.
And, stupid or not, Kamala jumped on it like it's name was Willie Brown.
Now I'm no lover of elaborate theories, but the idea that it's too dumb to try ignores the basic fact that someone did try at least 50% of it, and Kamala really did try to capitalize on it, so we're incontrovertibly 3/4ths of the way there. The only question now is whether they conspired in advance, and given their close prior relationship, it's at least worth considering.