There is constant rhetoric that the other side is evil. Often, that rhetoric goes to the very top.
Either that rhetoric is correct, in which case the other side is evil, or the rhetoric is incorrect, in which case your own side is evil (for promulgating and tolerating such a horrific and false accusation).
So at least one side must actually be evil. Maybe both, but certainly one.
I know that I've been accused of evil, quite often. That seems a pretty vicious and utterly unjustified accusation -- which I consider evil. So either I'm evil, or they are.
This argument isn't airtight, of course. I would expect people to reject the premises, or even if they do, not follow it to the conclusion I reach.
Still... once it reaches nearly half of everybody, I'd expect it to increase just under its own weight.