Not good enough to be the only standard form of communication permitted other than a handful of centralized proprietary apps.

A journalist or a dissident may wish to get critical communications out from a remote area without exposing their identity or location.

Then this isn't the solution for them. You keep assuming this is an internet service when it's not. Internet protocols are massively inefficient and have latency constraints that would choke narrow channels while offering almost no utility. This will be a modified SMS service, not a not an IRC service. Don't like it? Go buy an actual satphone with a data plan.

Whose goal is to solve this? Not T-Mobile or SpaceX

When you are the only source of a critical service in an area, you become a utility and should shoulder the responsibilities that come with that.

They don't have a responsibility to help you stay anonymous if they don't promise it. Follow your logic and we wouldn't have remote schooling or medical services over HF radio either. It extends the capabilities of normal phones to provide a feature we didn't have before, so you can't expect the capabilities of full fat, dedicated hardware. It's better than nothing, so why complain? You want net neutrality for a non-Internet service?