The way the United States went after Islamic extremism was a moral and practical disaster: the government lashed out almost at random, imprisoning Muslims virtually at random, attacking countries with no connection to the problem at hand, and instituting mass surveillance programs that produced virtually no results. The orgy of misplaced state violence which occurred in the aftermath of 9/11 was a powerful statement against Islamic extremism -- but the state does not exist to make statements.
Wars shouldn't happen simply to communicate that yes, we're taking this seriously. Arrests shouldn't happen simply to demonstrate a heightened level of suspicion. When states delegate the right to use violence on their behalf, those people to whom we've delegated have a responsibility to do what's effective, and what causes the least collateral damage, not what is most satisfying to those aggrieved by the state's failure to act.
I do not trust the laws which would empower the police to pursue white supremacists with omnipresent surveillance and indiscriminate violence. I do not trust the police implementing those laws to use them to the benefit of black Americans. I do not understand why anyone else would, other than -- perhaps -- as a metaphorical howl of despair that the official outlets of state violence can't be trusted to deploy that violence reasonably.