A U.S. radio host who mocked Heath Ledger's death live on air a few hours after his passing has been slammed by gay activists. During his Tuesday show, Fox News Radio presenter John Gibson played an audio clip from the movie Brokeback Mountain in which Jake Gyllenhaal's character says to Ledger's, "I wish I knew how to quit you." Gibson then told his listeners, "Well, he found out how to quit you." Later in the broadcast, Gibson played another Brokeback Mountain clip, this time of Ledger's character saying, "We're dead." The host then mockingly repeated, "We're dead," before playing the clip again. Gibson, who is on record as criticizing Brokeback Mountain as a "gay agenda movie," went on to label Ledger a "weirdo" who had "a serious drug problem" and speculated as to reasons why the actor may have taken his own life. Ledger, who was found dead in his New York apartment on Tuesday, is not thought to have committed suicide, according to authorities and his family. Rashad Robinson, a spokesman for The Gay & Lesbian Alliance Against Defamation (GLAAD), says, "Gibson's remarks are vulgar and disgusting. It's sickening that Gibson would exploit Heath Ledger's tragic death to promote such hurtful intolerance. And to do so at a time when family and friends are grieving shows a level of insensitivity that is beyond the pale." On his Wednesday show, Gibson refused to apologize for his comments, explaining they were just "a little Brokeback Mountain joke" and there is "no point in passing up a good joke."