To what extent do people have a responsibility to call out extremists in their group?

I’ve probably asked this question before, but I’d like to hear some new answers.

Is failure to condemn tacit approval? Should moderate right-wingers call out white nationalists? Should moderate Muslims call out Islamic terrorists?

If yes, why should they do it? To prove that they don’t “secretly sympathize” with extremists? To delegitimize them?

Do you distance yourself from extremists in the various groups you belong to?