The US proclaims itself as a free country, and 9dash has the right to voice his opinions as a citizen.
Besides, he states facts (genocide of native americans, meddling with and destabilizing other countries), and his opinion does not seem too far off the mark of reality, ala trade war, tech war and now drums of real war on the horizon.
If you are a democracy loving westerner, you should embrace the fact that 9dash can voice his opinions, in fact, you should be prepared to die defending it, to quote some American I can't recall the name of.