"shall not deny, limit, or restrict the ability"
They aren't really doing any of that are they? Do they say that LTE will never be available to you on your device? Or that you can only use it so many hours per day or only between such and such a time? I believe that is what would be required for them to violate these regulations. And it appears that they are acting within their legal rights to postpone their "mandatory inspections to make sure the devices aren't bugged with something that could disrupt their networks" or something. Are they doing it to gain a market advantage for a bit? Sure. Is it immoral? Maybe. But is it against FCC regulation? That's much harder to prove.
To say they are sidestepping regulation is one thing, or to say that they're being immoral for their corporate actions. But suggesting that they are violating FCC regulation is a statement of fact. A statement that could lead to you being sued with libel.
I'm not saying you are wrong to be upset, I'm just saying: be careful what you say.