Of course I'm not a lawyer, but when you make stuff and put it online? You have to know a thing or two to stay out of trouble. And you don't.
First of all: no, a license is not a contract. A contract has to be signed by both parties, otherwise it's null and void. And even if it was a contract, it could be canceled.
Second, I'm a volunteer moderator. Nothing I say here is official. Especially since this is about a project published on itch.io, where I have no authority as a moderator (it only extends to the community). Edit: in fact I pointed out repeatedly throughout my posts in this topic that I'm only expressing my opinions as a creator and player who is using the site like everyone else. Even our admins use their accounts the usual way.
Third: you seem awfully certain this can go to court, and you're making statements that sound threatening. I do not appreciate being threatened. You throw around awfully big words given the nature of this entire situation.
Once again, I am not a lawyer. I could be wrong about any and all of this. But your arguments don't convince me at all. And itch.io does have legal council. The real kind, for a change.