This theory is that rather than the change itself driving advertises away, it's outrage about the change that's driving them away. In which case they could be expected to only stay away for as long as the outrage persists.

I’m saying as long as brands can’t be guaranteed their ads won’t regularly show up next to horrific things, they won’t come back. Especially since they weren’t great To be fun with, having significantly smaller numbers of advertisers than their competitors.

Brands don't care at all what's next to their advertising. It is much more important for them to be on the right side of the conflict.