Significantly less secure at that. I imagine GP has iMessage disabled on their computer because other people use their computer, and they don't want iMessages/SMS going anywhere other than their phone.
Well, Telegram is by definition not as a secure as iMessage. Telegram messages are by default not encrypted on the server. Even when it is encrypted on the server, telegram has the keys and can decrypt it.
Telegram isn't as private as iMessage, but that doesn't mean it's not as secure. Security-wise, exploiting iMessage is easier than exploiting telegram, since iMessages has some special privileged access. Security doesn't mean privacy.
This is true (one is talking about zero-click zero days, the other is talking about “privacy,” not sure if they mean privacy against Facebook or privacy against other users of their device).
But the comment that kicked off the thread was the one about privacy.
I think they mostly targeted font/image/url parsing which are used across the OS. iMessage was somewhat privileged at some point in the back but was compartmentalized later and media processing was the only escape, but that’s out of process now too I believe.