Those who say this is an inappropriate comparison are gaslighting, as these criminals have a consistent track record of engaging in violence, intimidation, threats, and more. Let's take a look at what this subset of BLM protesters have done in the Seattle area. They:
1. Harassed the mayor at her house, and issuing death threats like "guillotine Jenny" and writing misogynist messages like "Resign bitch" on her house and the road in front, and used similar tactics at the houses of council members: https://www.seattletimes.com/seattle-news/politics/native-le...
2. Repeatedly blocking bridges and highways, snarling traffic for thousands of drivers, pedestrians, and bicyclists even after their irresponsible highway blockades led to a death: https://www.kuow.org/stories/updates-protests-for-racial-jus...
3. Showed up at our black female police chief's neighborhood, started documenting who lives where, noted license plates, and interrogated neighborhood kids for information: https://lynnwoodtimes.com/2020/08/02/hundreds-of-blm-support...
4. Even showed up at the houses of council members who agreed to their demands, to intimidate them and make sure they wouldn't change their stance: https://westseattleblog.com/2020/08/protest-evening-march-in...
5. Used a homeless camp as a staging area for riots, storing weapons there: https://www.msn.com/en-us/news/us/seattle-police-recover-wea...
6. Showed up at white people's homes, demanding that residents leave the neighborhood: https://www.bizpacreview.com/2020/08/14/blm-marches-through-...
7. Made lists of businesses to destroy: https://thepostmillennial.com/antifa-rioters-made-lists-of-s...
How can you not see the valid comparison to brownshirts here? Damaging property, holding drivers hostage on the highway, obstructing others from accessing public infrastructure, committing arson, issuing death threats, and so forth all match the description perfectly. Remember, terrorism is defined as "the use of violence and threats to intimidate or coerce, especially for political purposes." (https://www.dictionary.com/browse/terrorism). The actions of local BLM activists and Antifa rioters completely fits this description.
And given the evidence is so clear, this attempt to cancel Cliff Mass, a distinguished Professor of Atmospheric Science at a major research university, is simply progressive cancel culture run amok.