I never said there was anything prohibiting them, just that they will be losing users. (Although, blocking some access can be illegal, for example when accessability tools are blocked.)
There's a whole spectrum of gatekeeping on communications with users, from static sites that broadcast their information to anyone, and stores that let you order without even making an account, to organizations that require you install local software to even access data and perform transactions. The latter means 90%+ of your users will hate you for it, and half will walk away, but it's still very common, collectively causing business that do so billions of dollers a year. (https://www.forbes.com/sites/johnkoetsier/2021/02/15/91-of-u...
to-install-apps-to-do-business-costing-brands-billions/)
When companies get big enough to have entire departments devoted tasks, those departments will follow the fads that bring them the most prestige, at the cost of the rest of the company. Eventually the company will lose out to newer more efficient businesses that forgo fads in favor of serving customers, and the cycle continues.
I'm just point out how a new fad is hurting businesses, but by no means wish to limit their ability to do so. They just won't be getting my business, nor business from a quickly growing cohort that desires anonymitiy, or even requires it to get around growing local censorship.