Seems the author of the article do not have any idea of security. Signal is ZERO security product. Protocol is interceptable (i have done it), and also it ask for a phone number which could be attack by NSO group exploits or even ss7 exploits. Tor is also interceptable now.
If you need something secure, code your own software.
Signal uploads your contacts to their server and also they could disable encrypton from closed command and control server.