It'd be interesting to see Google decide to charge a premium for ads on climate denial videos - pass on no more than the normal share... and put the extra earnings towards fighting climate change. Essentially: a climate change denial tax.
I distinctly remember advertisers saying they would put their ads on demonetised content featuring guns after they banned ads from such so it’s not impossible that some advertisers would be okay with their ads on some controversial content.
How could they have, this is a brand new change. I doubt they asked all advertisers there opinion. The assumption that all advertisers are in agreement on this topic is almost guaranteed to be wrong.