There are times violence is necessary, with Nazi Germany being the classic example.
That said, most of the time, even for many times where violence might be “right” it’s still a strategic error. It’s much harder to build than destroy and any “successful” deployment of violence requires physical and institutional/relational rebuilding.
Violence can make it harder to attract supporters to your cause. It gives your opponents the feeling of moral justification in also exercising violence. In a full on conflict, it reduces the ability of key supporters (the young, elderly, disabled, many women) from contributing to the struggle compared with non violent action