Thank you for raising this! I work for a firewall vendor myself and its drives us mad when competition uses the word URL when they can only look at SNI in a TLS handshake. By competition I mean most others are doing it too.

I guess one of the reasons they choose to say URL over FQDN or hostname is that the latter two are less likely what typical developers might venture out looking for - but I could be wrong. At least the requirements when they emerge would want URLs to be whitelisted and that is what the intercepting proxy world had been delivering.