Oh don't worry Nate, I wasn't really upset- however since HBO and Showtime have been available on nearly every cable system in the country for 30 years I doubt that there are many people who haven't heard of them.
But when people subscribe to things like HBO they know they will see (and want to see) adult content. People watching basic channels like CNN or Lifetime don't so these channels don't want to offend even their most prudish viewers.
Of course even HBO is not uncensored- they don't show anything truly pornographic. Even the Playboy channel only shows soft-porn. For hardcore you'd have to go to something like BlueMax or Ecstasy. And while the FCC may not control what cable systems show- many city franchises do- and prohibit them from carrying true porn.