That’s not true. Skepticism is good and welcome. Random allegations like “it has a backdoor” are not.
If someone has demonstrable evidence that Signal is compromised, I’d delete it immediately. Until then it’s just unwarranted speculation, seemingly intended to make people “both sides” it and switch to something more popular and less secure.
I would never, ever trust anything that asks me to login using my phone number - which by nature is identifier. They have their own motivation to require phone number - but I will never buy this kind of things.
That said, being open source doesn't mean it's private - at the very least they can collect enough metadata tied to my phone number. If my messages are sent via centralized servers owned by someone other than me who already have my identifier, there is no reason I have to trust them.
Saying something against Signal always hurts some people's feelings, as if Signal is sacred object.
There, I said it. You are free to downvote me. But that won't change the fact that they have collected data, just like WhatsApp et al.
I’m not saying that article is wrong. I’m not going to read through that wall of text and vet every unlikely claim. I am saying it could hardly be more opinionated, directly calling the Signal team liars. Even the site’s own header throws a large grain of salt at it.
That was my first impression, too. I saw a couple of specious claims and stopped looking.
I’m not a Signal fanboy but I’m suspicious at the amount of unmerited criticisms it gets from random posters. My inner conspiracy theorist keeps whispering that people want us to stop using it.