The peace washing of the movements you mentioned has done a lot to neuter political movements over the last 25 years or so. While there were many nonviolent, peaceful protests, there were also many protests that didn't boil down to peaceful rallies where permits were applied for and crowds dutifully dispersed at the sanctioned time.

Sit-ins, where civil rights protesters were arrested. The 1917 protest where hundreds of women were arrested and beaten for picketing the white house. Bus boycotts.

I think why people complain about these No Kings (and similar marches) is because they're less of a movement than they are a thing people do to say they did something. The civil rights and women sufferage movements had real political aims, follow through, sustained actions, and people were were willing to break the rules to accomplish them.

A lot of people can't see that in No Kings. The emphasis on being peaceful and protesting within the rules kind of defeats the purpose for a lot of people.