Highly dependent on what state you’re in. Myself and others have legally carried at rallies, protests, and BLM. Cops don’t like armed minorities and leftists, but presently they’re still obliged to tolerate them if you do so well informed of your rights and within the confines of the law (like not being able to enter certain buildings, and obviously not using them to threaten someone).

This is why community planning is important. You can’t control who all is going to show up to rep for the cause, and you can’t predict who’s going to show up armed. You can encourage attendance to pre-event planning, figure out who will be there and with what, then coordinate their involvement to lessen the likelihood of escalation without discounting that guns are a psychological show of threat of force and a worst case scenario defense, as well as make sure they’re aware of their rights, the law, and what to do if a cop decides to overstep their authority and harass. You teach deescalation for when the counter-protesters try and spark a confrontation. You plan for if and when supporters you don’t know arrive armed, how to approach, how to figure out if they’re well intentioned, allies but extremists, or an agent provocateur.

The cops do not want an armed populous, and those 20k people who were armed during that protest where not cops.