No, it's really not. If I unregister from iMessage the last thing that should happen is my Apple ID swallowing messages from people's iPhones.
Return an error or redirect to SMS, it's not that fucking hard.
The one thing you are right about is that it's an intentional dark pattern on Apple's part to obsfucate Apple IDs and phone numbers. It's an illegal anticompetitve strategy.
No, you're misunderstanding what's happening. If you unregister your phone number from iMessage, then that's the end of it. People sending messages to your phone number will get SMS messages. It is impossible for a de-registered phone number to receive iMessages on an iPad. What's actually happening is that the people who are sending you messages are sending them to your Apple ID instead and iMessage is always registered to an Apple ID so the messages are delivered to your iPad. It's not swallowing anyone's messages from people's iPhones because that's literally not possible.
It's not a dark pattern. It's not an illegal anti-competitive strategy. It's a successful delivery of a message to the recipient address it was sent to that you're simply misunderstanding.
Yes, you are misunderstanding. I don't see how that's not obvious to you. iMessage is tied to an Apple ID. Unregistering your phone number from that Apple ID doesn't turn iMessage off. The fact that you think it does is where you misunderstand. The only way to turn off iMessage from an Apple ID is to turn off iMessage for the devices that are set up to receive those messages.
It's literally impossible to send an SMS message to someone's Apple ID and it's not possible to send an iMessage to a phone number that's been unregistered from iMessage. Just because you don't understand how it works doesn't mean Apple is at fault. You cannot delist an Apple ID from iMessage, you can only sign out of iMessage on a receiving device. That's it. Anything else above that is your fault.
If you don't want to receive iMessages at all and don't want people sending them to you, sign out of iMessage. It's not that hard.
Return an error or redirect to SMS, it's not that fucking hard.
The one thing you are right about is that it's an intentional dark pattern on Apple's part to obsfucate Apple IDs and phone numbers. It's an illegal anticompetitve strategy.