Refusing to disperse isn't a violent attack on the government. At best, when BLM protests do become violent, they are riots. Until a BLM protest attempts to use force to overthrow a city, state, or federal government, it's a riot at best when violence is involved.

I've not seen anyone having a problem calling BLM riots riots when they happen. I've seen a lot of people struggle to call Jan 6 a riot or insurrection.