I’m not being glib. Honestly, why can’t I? There’s precedent for saying that’s unauthorized access, so the feds (not the state; “Interstate Commerce Clause” and all that) should prosecute the visitor for violating my ToS.
So, I'm genuinely curious about this. Does the US not require any kind of territorial nexus in order for a jurisdiction's laws to apply to an individual? Can Texas criminalise abortions in New York, by New Yorkers, for New Yorkers? This seems very unlikely to me.
Under private international law, very generally speaking, you tend to require a nexus of some kind (otherwise, we'd all be breaking Uzbekistani laws constantly). I assume there must exist some kind of nexus requirement in US federal constitutional law too.
Assuming you have no presence, staff, offices, or users in a state, and you expressly ban that state in your T&C, why would that state's laws apply to you at all? You're not providing any services from or to that state, and in as far they can open your landing page, that's sort of like saying they can call your phone number. And in the absence of that state's laws applying at all, would not any requirements about geoblocking etc that may exist in those laws be moot?
(Usual risk calculus would seem to apply re over-zealous state prosecutors, etc.)