and are using that to connect to the iMessage servers.
This is not allowed because Apple doesn’t want to allow it. They own the infrastructure serving the API, they get to determine who is authorized to use it. They can block whoever they want. And technically speaking, using it in an unauthorized manner could even rise to the level of a criminal violation of the CFAA.
It is literally impossible to do as you suggest (use entirely their own resources) because iMessage is centralized and cannot federate with any other server, even if one did exist.
Partially correct. It is not impossible to do as I suggested, because I never suggested that they should have interoperability with iMessage.
Yes, this part is legal and fine.
This is not allowed because Apple doesn’t want to allow it. They own the infrastructure serving the API, they get to determine who is authorized to use it. They can block whoever they want. And technically speaking, using it in an unauthorized manner could even rise to the level of a criminal violation of the CFAA.
Partially correct. It is not impossible to do as I suggested, because I never suggested that they should have interoperability with iMessage.