It's possible that the commission will require ISPs to block non-backdoored TLS. But I'd consider that to be more of a worst-case scenario, rather than something that's particularly likely to happen. More likely outcome is companies that store user messages on their servers won't be allowed to provide end to end encryption, and would be forced to store the messages on their servers in plaintext, or using backdoored encryption. The bill allows for differing requirements for different kinds of services, so hopefully ISPs would not have much of a change from the current situation.
Of course, even just that scenario is bad enough. It would mean that the police, the FBI, the NSA, people at the messaging company, and hackers who breach the company's security would all be able to read those messages.
Of course, even just that scenario is bad enough. It would mean that the police, the FBI, the NSA, people at the messaging company, and hackers who breach the company's security would all be able to read those messages.