[chao-]

Depends a lot on the community's topic, purpose, and size.

However, a sign that someone needs to be removed is if you find that the community writ-large treats them as a Missing Stair [0]. If they have refused direct requests from community moderators/leaders to address their behavior, or regressed after a short period of improvement, and if most of the community is required to do work to actively manage their toxicity, that is not sustainable.

It is a mistake I once made in managing a community. There was a person who was able to present as "pleasant enough" when the situation called for it, but who was often toxic when something didn't go perfectly (especially in a 1-on-1 setting). I allowed them to stay for too long, and the community as a whole suffered from the ambient sense of tension and hostility.

[0] https://en.wikipedia.org/wiki/Missing_stair

[miladyincontrol]

By large I absolutely agree with te premise, but find too that sometimes you find someone akin to a hammer looking for nails, starts to label anyone a missing stair over the slightest incompatibility. Oft combines with a formation of a faultless in-group and a perpetual need for new villains.

Its a rare thing, I dont mean to suggest its common. But it is always awkward to see when some people learn such language just to turn it into a cudgel.

[chao-]

>sometimes you find someone akin to a hammer looking for nails, starts to label anyone a missing stair over the slightest incompatibility.

I 100% agree. This is why it is important for leaders not to rely on the judgement of a single person, but on the behavior of perception of the community as a whole (which I tried to mention as a caveat in my comment).

On the other hand, if you have an overeager moderator with too much discretionary power... well that's a different community problem, and it is going to go wrong in multiple ways, not just this one :(