GadolHadofi:
Yes, it is actually very hard to understand.
There are way more Muslims (whether Jew-hating or otherwise) and Jew-haters than there are Jews. If you think this is a numbers game, then it’s over before it started. That’s not the reason.
That “Due to the great concern” nonsense was from the secular organizations, not from Agudah; they just parroted/forwarded the email.
The rally poster lists three reasons to rally:
March for Israel, March to Free the Hostages and March against antisemitism.
This march will, of course, accomplish none of that (May Hashem please help all Jews immediately, regardless), and it is actually heretical to think that it could accomplish that last one. The first one is also a chilul Hashem, even if the intent is only to support our brethren there.