Here's a lesson from Uncle Joe's School of Common Sense.
Q: Uncle Joe, what is the function of infantry on the battlefield?
A: Infantry uses fire and maneuver to close with and kill the enemy. They normally have air, artillery, and armor support.
Q: Does the US military have experience in urban fighting?
A: Sure does. Got a ton of it in the Middle East. You have many officers and noncommissioned officers with such combat experience. And those lessons have been passed on to every infantryman.
Q: Do you believe BLM, Antifa, or any right-wing militia could defeat US infantry (Army/Marines/National Guard) in urban or other combat?
A: Not a chance. Individual infantrymen would be wounded or killed, but their opponents would be waxed. Infantry are not police. When they clear a building, they aren't going to announce their presence with words, more likely a boot to the door and a grenade thrown in. They WILL clear the building. And the next one, and the next one. Any dumbasses on rooftops who think they'll stop the infantry will be killed by snipers and/or air support. The infantry will kill the enemy until they are ordered to stop. Most of you may not realize it, but the US military is a very effective killing machine. So you see a platoon of "black militia" dressed in black, with small arms? So you see a platoon of right-wing militia with their small arms/machine guns, and their trucks? Care to guess how long they'd last against a platoon of trained infantry? Not real long. They would be out-trained and outgunned, not to mention outdisciplined. The normal reaction of most civilians when they hear an explosion or gunfire is to get away, freak out, or both. Infantry and their air/armor support go forward. Even most veterans in the militias with combat experience would be up against it. They may be able to fight effectively, but they might be fighting pretty much by themselves, when their non-veteran comrades realize this is no longer a game and beat feet out of there. Then it will be fight or flight time.
Q: Uncle Joe, I don't think I want to fight trained infantry. Maybe I should stop thinking I'm Billy Badass and start working for peaceful change in my city.
A: That's right. Behave. You'll live longer. The infantry/gunships/armor won't want to kill you, but they will do it.
(We aren't talking a civil war here. We're talking a city or cities where things have gotten so bad law enforcement can't effectively quell the disturbances. Personally have seen regular troops deployed in a rioting city - Detroit, 1967. Things started calming down real quick when the regulars showed up.)