“some people use” ≠ “everybody wants to use”
(And are you sincerely suggesting WhatsApp, which is run by one of the largest and most aggressive privacy invaders the world has ever known, as a privacy friendly application? I would suggest re-thinking that position if you want to be taken seriously.)
The guy I replied to is saying that not everyone wants to use Signal because it’s centralized and based on phone numbers. But billions of people use WhatsApp despite being exactly that. Signal nails the privacy stuff but obviously people don’t give a shit because they’re using WhatsApp anyway.