I'm not a specialist, but there's a chain of trust you need to maintain to have the full set of features. If it's ever broken, you're sent to the gulag. I broke the chain when reinstalling like an old-timer on my M1 Macbook Air and was then forced to enter my password twice to unlock the Mac.
I had to reflash with a second Mac to restore the chain.
I remember reading (perhaps here on HN) that Apple does weird/nonstandard things to wifi packets to enable Continuity/Handoff features, so it could be related.
The application can see that the kernel is tainted and refuse to run. Similarly, some kernel-related functionality may be disabled. None of this requires iMessage to run in the kernel or have a module of its own.
