It’s impossible to escape the surveillance of those three letter agencies. We only got a brief glimpse into the other side of the curtain back in 2013, and there is no idea how advanced their surveillance technologies are, so why bother for a normie?
It’s also painstaking if not impossible to wipe all your metadata from the internet, which can later be mined to infer personal data and sold by data brokers. Not to mention that people have jobs and use their credit cards, no way even to hide the most important personal identifying information.
So using Signal, despite being centralized, is not too bad at all. Very few people can totally sacrifice convenience for privacy.
It’s known as false dilemma, a logical fallacy.