I've been doing a lot of work with 50501/Indivisible recently. Because my account is somewhat linked to my real identity I can't be too specific or critical. But here's my take:
"Kool Karyn" is almost definitely a member of Indivisible, a nationwide Liberal anti-Trump org whose membership is almost exclusively old, middle-class, white liberals.
In my (majority-black) city, a majority-black protest of 30 will get drones and snipers and tear gas. Indivisible got 2,500 (almost all older, white) people out at a public park protest and the only cops we saw were probably just on their regular patrols.
I'm gonna punch against the grain: Karen is giving perfectly reasonable advice for her contingent, for the kinds of protests that her organization is organizing. You can criticize their politics, their strategy, their class relations - but cops are not going to drive an AV through a crowd of kneeling white boomers. And the way her post is phrased, at least, does not imply that she is giving general advice to all protestors - just the people going to this particular protest, which will almost certainly be 90% old white libs who are in practically no danger of police violence.
And just like a bunch of black students were shot at Jackson State and no one cared but when a few white students were at Kent State it was suddenly a big deal, if the old white libs do come under fire, the public and media will care. And, for their politics and class position, that's actually somewhat brave - old white libs are never going to riot, but (and trust me, I don't mean this in a hateful way) the most useful things they can do at a protest that is within their temperament and ability is commit to nonviolence and have violence brought unto them by the state.