Pure horseshit. Access to supercharging is a service that Tesla chooses to make available to their customers, not some right of the car owners. So long as they aren't being discriminatory, Tesla can choose to limit that offering in any way they'd like without fear of legal repercussions over the impact of those changes. They could announce at noon tomorrow that as part of a cost cutting plan they were shutting off all superchargers effective immediately and no one could say boo to them. They'd have a lot of angry customers and probably lose any chance of selling most of them another car, let alone scaring off many/most of their potential customers. But that's it. Unless people happen to have some previously unannounced contract with Tesla wherein Tesla has guaranteed them access to supercharging?
I mean, this is still America, so anyone can sue for anything. But anyone trying to sue Tesla because the 80% supercharger limit resulted in problems will have to hope that Tesla chooses to settle their nuisance case out of court because there is absolutely no way they win such a case on the merits of the situation.