No it isn't what? Protected under the Constitution?
Why do you think that even though a significant portion of the country hated it, that the Black Lives Matter protests and marches were allowed all across the nation? Because they ("the people" of Black Lives Matter and their allies) were assembling and protesting in accordance with their Constitutional rights in order to let their government know that they wanted their grievances redressed (for the police which is a government agency, to stop unlawfully killing Black people).
Why do you think that more than 700 people who participated in the attack on the U.S. Capitol on January 6th 2025 ended up with criminal convictions? Because they were not peaceably assembled (or at least they didn't stay that way), they engaged in threats & violence and violated a plethora of laws. Yet many seemed to think that their actions on that day were comparable to the peaceable Black Lives Matter marches & protests and appeared to be angry and surprised to discover that no they aren't the same set of circumstances.