Friend, the issue isn’t freedom of speech. It’s breach of contract. The establishment has policies which are the contract for using the designated space. If you breach those policies you are in violation of said contract that deems you ineligible to participate within the establishment.

You do not have the right to intrude on other people’s establishments after being asked to leave for violating their written terms of service without being accepted back.

Edit: for example, Lemmy.world has a rule of no advocating for future violence. Do I agree with it? It does not matter. They created the policy and it is their establishment. If I advocate for future violence they can ask me to leave, and if I argue with them they very well may ban be from posting/commenting there. It isn’t my freedom of speech that they are banning, it is my access to their establishment.