[gjsman-1000]

You are trying to say that iMessage does not have forward secrecy.

That's true, and is a perfectly legitimate reason to use Signal.

I'm saying that the OP was dissing iMessage because of the Pegasus zero-click exploit, and was saying that switching to Signal gives zero guarantees of protecting you from that, because it likely has it's own zero-click exploits, especially because it doesn't attempt to sandbox unlike iMessage does with the flawed BlastDoor.