> If we can be accused of anything in this context, it's not kicking bad people out aggressively enough, which seems very different from fostering bad ideas.

It's not very different. It's barely different at all.

Right now, I have five tomato plants growing in my garden. Two of them I planted; the other three grew from seeds left in the ground by tomatoes that dropped from plants growing last year. All I did was refuse to uproot them when they sprouted. Five healthy plants, with different origins, but the differences are largely insignificant.

Groups and behaviors are much the same way. I've worked with hundreds of moderators over the years who wished to keep their hands clean and yet express some sort of dismay as to the sorry state of the communities they were nominally responsible for... Such moderators, like a gardener who does not want dirt under their nails, are best encouraged to find other hobbies.