Let’s roll with your interpretation that the slogan is solely Antizionist. That would make the poster misinformed and incorrect; in this situation, the right thing to do is to talk with the poster, informing them, while checking their profile for potential Antisemitic activity. This also works great when the user is not rational (i.e. a bad faith agent) because it gives you better grounds for a ban.
Another issue that I see is ban length. A short ban is great as a warning, or to tell the user to cool their head; while permaban is great when you want to convey “we the mod team do not you here, fuck off”. A two months ban is the worst of both worlds.