They don't just do nothing. It's worse than that.
I guarantee if there was someone standing next to her with an Israeli flag, they would consider this woman branding this genocidal antisemitic message as the "good one" and the Israeli supporter as the "bad one". Such is their prejudice they have now lost all ability to see right from wrong.
Hence here so many of them are reframing burning babies, rape and cold blooded murder of innocent civilians as "resistance". There is no form of "resistance" that actually looks anything like that, but their prejudice against the ole star of David is now so deeply ingrained, we have almost become monsters in their eyes - undeserving of even basic empathy.
I have watched antisemitism creeping into the mainstream, particularly via the "anti imperial" left (who don't understand what imperialism is) and it's been a slow but powerful process.
Bit by bit, each person contributes their little bit - subtle, but chip chip chip of sharing blatantly antisemitic words, images and ideas to millions via social media and making it en vogue to persecute Jews again, and it works rather like advertising.
It poisons the minds of people to generally dehumanise Jewish people to a point this woman is standing in the middle of a protest in broad daylight - purportedly advocating for HUMAN RIGHTS, whilst brandishing a sign that Goebbels himself might have felt too direct.
And I saw the video of her on Twittter explaining herself, and she has not the slightest clue what she is talking about. It's clear she keeps looking at her friend for instructions for what to say. It's clear she hasn't even got the most basic information needed to have any kind of opinion at all. Yet here she is, believing herself to be actually virtue signalling because the left wing have "made antisemitism great again".
And I am left wing myself!
This is how the majority of the population of this world was convinced for millennia that Jews were evil, bad, worthy of all the hate - simply by everyone just going along with it. How they don't feel icky, I will never know.