Earlier quoted context omitted.
That is, unfortunately, unworkable. You cannot successful quarantine toxic people from non-toxic people in the same community. People who aren't toxic rarely want to spend their time around toxic people, and those that don't mind it are usually those who aren't the targets of the toxic people. A community with many members who are openly white supremacists might not be uncomfortable for other white people -- even if…
See my sibling comment. Should we (society) have quarantined and de-platformed homosexuals when they were (historically) considered "toxic"?
You cannot effectively allow people to individually "filter out" toxic behaviour within a community because toxic behaviour permeates all aspects of participation in a community. The views we hold are fundamental to all aspects of our lives: our lives are built upon our views. A violent anti-semite's beliefs are present in their views on politics, religion, video games, food, housing, travel, science, technology... you cannot effectively "filter out" the fundamentals of someone's view points without neutering their speech -- which is no different from de-platforming them.
A community is a group of people and a group of people is a collection of beliefs, a community is not a bunch of people who use the same website but are intentionally siloed because their beliefs are incompatible. People who favour the PlayStation 4 over the Xbox One can be part of a community with people who favour the Xbox One over the Playstation 4, but can people who wish death upon all jews be a part of a community with jewish people?