The Seattle Police Department, likely at the orders of their political superiors, stood by and watched until 7ish, when they finally made arrests of the core group demanding to be arrested.
If you want to protest, fine and dandy. Yump up'n'down on the sidewalks, dance naked in the public fountain, scream crude comments at passerby. Wave signs. Do performance art. Run for office. Vote. Write a nasty letter to the editor. All good.
Obstructing traffic, because it obstructs access by emergency vehicles and interferes with others trying to simply get home - not so much. My sense of humor on such topics is exhausted amazingly quickly.
Book'm, Dano. Reckless Endangerment, obstructing a public thoroughfare, and jay-walking. Then seek out pro bono attorneys to sue them on behalf of all the drivers and businesses inconvenienced by their public temper tantrum - and stand well back.
If it's a big enough deal to protest in the streets...have the guts to take it to town, complete w/ arrests, riots, and serious litigation. Or stay home, and do something sensible.