Couldn’t it just be that they’re using something like bcrypt which won’t take any chars above its limit into account (knowing that there’s a limit will pretty much never matter to a user but why obscure the fact)? What does it even mean to store it reversibly, just because they have a char limit doesn’t mean they are encrypting the password, could just be some frontend shenannigans as well.
It really is an almost impossible situation. The far right will win this one regardless what the government does. If they do nothing we will probably see some form of terrorism sooner or later, if they clamp down on it they will prove the activists right in that the government will reduce freedom of speech just because some muslims cant behave.
Maybe theres some way to eke out a win but I cant see it.