Beyond the general history, this is a big ask of the protesters when one of the primary motivators for this specific protest is distrust of the police.
The political class had collectively decided they understood protests, that people would turn up peacefully, shout some slogans and then go home.
But that's not what a protest is. A protest is a clear and specific message "this is how many people took time out of their day, free time, time off work to come and represent themselves for an issue - do you think it's wise to ignore them?"
Decade? More like century. The labour demonstrations in the 19th and 20th century were ignored until they got militant. Nothing's changed since then in the US.