Simplex let's you run your own server and uses disposable IDs.
Signal could be censored in a block the entire account sense but they wouldn't be able to block specific content or know what you sent to honeypot it. At most who messaged who and when.
This person clearly just has an ax to grind.
I'm getting sick of people slandering every encrypted messenger that actually works. The result isn't that they switch to your messenger that is so secure even you can't see your messages. The result is they just keep using plaintext.