During the live show of "Manos" The Hands of Fate,Torgo's first appearance is greeted by applause from the audience. Remember, this was the actor's only role, and he tragically committed suicide shortly afterwards. Now his very appearance draws cheers.
And anytime Torgo gets a mention in a live show, it gets cheers. When they did it during the Santa Claus Conquers the Martians, the guys basically state they're pandering to the fans. That's how beloved he is by Rifftrax fans.