Following the conversation down, it sounds like what you're really saying is that Signal stores sensitive information encrypted with PIN+SGX, which is controversial. And maybe you have a good argument for why it's bad (and I'm uneasy with it myself). But I think people don't like that you made the assumption for them that PIN+SGX is bad.
Even if everyone agreed that the system was secure, and they absolutely don't, see for example
https://web.archive.org/web/20210126201848mp_/https://palant...
https://www.vice.com/en/article/pkyzek/signal-new-pin-featur...
I think we should all agree that outright lying to users on the very first line of their privacy policy page is totally unacceptable.