Do people who run the centralised, private Signal app have more power over the user than people who run decentralised, non-private Mastodon instances? Or do Ma

Do people who run the centralised, private Signal app have more power over the user than people who run decentralised, non-private Mastodon instances? Or do Mastodon people say it's strictly for broadcasting and encourage people to use proper end-to-end encrypted messaging apps for private communication?