It's like a company buying all the land within a 100 mile radius and then nominally "selling" plots to people but with terms of service attached that restrict what you can do with the land you bought and that allow the company to change the terms at any time. And then, after people have moved in, most of them having not even read the terms or realized it wasn't an ordinary sale, they start enforcing the terms against competitors. Which most people don't notice because they aren't competitors, and because the terms also prohibited anyone in the city from telling people what's going on[1]. Then people eventually notice and start to ask whether terms locking out competitors like that are an antitrust violation, and someone says that they're not because the people there agreed to them.
But how is an agreement prohibiting people from patronizing competitors not an antitrust violation? It's not a matter of who agreed to it, it's matter of what they're requiring you to agree to.
> nominally "selling" plots to people but with terms of service attached that restrict what you can do with the land you bought and that allow the company to change the terms at any time.
[1] https://som.yale.edu/sites/default/files/2022-01/DTH-Apple-n...
But how is an agreement prohibiting people from patronizing competitors not an antitrust violation? It's not a matter of who agreed to it, it's matter of what they're requiring you to agree to.