Yes, the term was coined ultimately in reference to YouTube, and YouTube was itself ultimately named in reference to CRT — but if you type “tube site” on Wikipedia it redirects you to the article “Porn 2.0”, and if you search “tube site” on Wiktionary it only lists a pornographic definition, and anecdotally I have personally only ever seen the term used in reference to porn.
Yes, the term was coined ultimately in reference to YouTube, and YouTube was itself ultimately named in reference to CRT — but if you type “tube site” on Wikipedia it redirects you to the article “Porn 2.0”, and if you search “tube site” on Wiktionary it only lists a pornographic definition, and anecdotally I have personally only ever seen the term used in reference to porn.