These stats are based on 2020, a year dominated by millions of BLM/Antifa rioters, protesters and looters. Culminating in the largest number of protests (and the most violent) in US history.
Resulting in dozens of deaths; tens of thousands of arrests; 2000 injured police officers - many seriously; one Federal officer assassinated in Oakland CA while protecting a federal building; billions of dollars in property damage; hundreds of arsons; dozens of federal buildings/court offices/police stations vandalized/set on fire/destroyed; the deployment of over 60,000 National Guard; plus Federal agents (FBI, DEA, US Marshals, DHS) to at least ten cities; the implementation of “lawless (CHOP) zones” in numerous cities that enabled violence, sexual assaults and murders.
So the results of this very focused study is hardly surprising lol. It’s a gross understatement to say, the leftwing kept the US police very busy in 2020.