And sometimes the good is used to spread the bad, or the whole. Cults sometimes recruit like this, abusive people can be nice at first, narcissistic traited particularly, violent fringe groups offer camaraderie, yakuza doing charity and relief supplies. So I agree 100% that it really matters where the good is coming from.
> Sure, the Klan has some bad hombres, but we also run Checkers Tuesdays, maths tutoring for underprivileged youths Friday mornings, and Bible study Sundays.
That is, at some point, the bad overwhelms any good.