For those motivated by self preservation and not principle, consider this:
If you join the righteous mob because it’s safer than standing against it, then when the mob disperses, the few who were courageous enough to stand up to the mob might remember your role.
Do you really want to take on those courageous types once the mob no longer has your back?
... ask the many French women pictured having their heads shaved by the townspeople after France was liberated from the last authoritarians intent on global empire...