OK. I went back and re-familiarized myself with the J20 trials. A group of about 200-extreme left wingers marched in protest of the Inauguration of Donald Trump, as a group. Individuals in that group broke the windows of private companies and parked cars, doing about $100,000 damage according to the prosecutors. All 200 were charged. Some 21-pled guilty to minor charges. All of the ones who went to trial were found not-guilty and about 140-had all charges dropped.
If the 1-6-21 attempted coup was equal to this non-event, the thousands of people outside of the Capitol Building who were involved in extreme protesting would have been rounded up, arrested and charged with violating the Washington, D.C. law against rioting, as upheld in US v Matthews.
It is probable that three things figured heavily in the government's decision to not pursue this path. The first is, it was a failed strategy in 2017-2018. The second is that they barely had the police necessary to expel the hundreds of rioters from the Capitol Building so that the Congress could continue to do its important business. En-Masse arrests would take many times the number of cops and National Guard troops available that day. The third reason is that Right-Wing extremist Jeff Sessions personally oversaw the J20 prosecution. Currently, the Justice Department is functioning independent of the political interference that was well documented in the years they were under the thumb of the Tangerine Tyrant.