re: Military in DC - I am legit confused

Well... having lived in DC I can answer part of this.

Believe it or not 15k National Guardsmen will be hard pressed to present a large show of force throughout DC because you can't swing a dead cat without hitting a massive government building. And they need to guard those buildings 24 hours a day.

The Capitol Police Force is, to be frank, broken right now. DC itself is carved up into little police fiefdoms so the DC PD probably only has access to something like 50 percent of the city.

If you want to keep trouble from breaking out you don't go with the absolute minimum amount of personnel you think will do the job. You go with a modified version of the Powell Doctrine. You use over whelming force and keep crazed dingbats from doing stupid things.

This is what they did during the BLM protests but they brought in the Border Patrol and the Bureau of Prisons personnel as well as Guardsmen.