When ABC slapped a parental advisory warning on this week’s episode of “Ellen,” in which lesbian lead Ellen DeGeneres jokingly kisses her heterosexual female friend, DeGeneres said she would walk out if the advisories continued. ABC put a “TV-14” rating on this week’s episode, and will not allow an episode where the script calls for Ellen and her girlfriend to enter a bedroom together. “This is blatant discrimination,” she said. “This advisory is telling kids something’s wrong with being gay.” Degeneres said that the only other show that had that label was “NYPD Blue,” which contained nudity and violence. ABC executives appeared willing to let DeGeneres quit over disagreements on how to handle gay themes, despite the fact that “Ellen” is one of few ABC successes this season, ranking eighth among all prime-time shows for viewers between 18 and 49.