This isn't at all the gotcha this person thinks it is.
Martin Luther King Jr. called for nonviolent resistance. The people resisted nonviolently, including Bernie Sanders. The media lied and called them violent, but MLK Jr. continued to call for nonviolent resistance in the face of that, and it worked.
Here, Bernie Sanders is doing the exact same thing. He's not suggesting that the protestors are violent any more than Dr. King was, as satirized by the propaganda cartoon. He's just doing the exact same thing - call for nonviolent resistance. No more, no less.
I know nuance is dead, but it is just insane to think this is a "gotcha." This person is the one "leaning into the hysteria" by assuming a call for action by itself is actually a condemnation of the protests.