Because of propaganda and state power. It’s not a symmetrical conflict.

They don't have to, but data shows over and over that non violent ones more often end to being more successful at regime change.

Benefits for the non violent:

• more people are willing to join protests
• much harder to use force to squash protesters (they can still try, but that often motivates more people to join, that is what for example happened in Euromaidan)
• it is much harder to frame that those protesters are there to hurt ordinary people
• sends signal for good people in power to do the right thing and that we have their back
• validates people that they aren't alone and that it is a lot of us

We actually have more power than them, they only succeed if we get scared and think there's nothing we can do. It becomes a self fulfilling prophecy.

Basically, if we start shooting, that will result in a military response, and the US military is really good at massacres.

Just look how stupid the administration is sending troops to Portland because all of the "violence". If Portland was more violent then they could carry the narrative rather than people dressed up in costumes. People will remember the frogs and the absurdity of the situation.

Both should, one does. Don't sink to their level.

Because violent revolts elevate violent leaders. Because violence is the last, worst option for influencing the behavior of your fellow humans. Nonviolence isn't more effective than violent political action if all you want to do is swap out who's in change, but it is more effective (I would argue necessary) if what you want is a nonviolent society governed by a nonviolent democratic government. Once both sides have devolved into violence, really the only thing that sets policy is which faction is able to inflict the most pain. It also proves the fascist rule of "everyone is ultimately violent, so your best bet is to stick with the violent team that shares your religion / skin color / flag / etc." and dominate through might, rather than trying to build a genuinely peaceful coalition that could, if empowered, build a genuinely peaceful government that makes its citizens' lives better.

Or, to put it another way, you can use The One Ring to defeat Sauron, and you may succeed in defeating him, but you will corrupt yourself in the process and become the very thing you sought to destroy.