I predicted this before they even mentioned that. He's probably self-loathing and hating himself for not being able to accept who he is.Thus his anger towards LGBT stems from somewhere deep inside.
I don't think his religion was as big a factor as his own personal identity crisis. He also claimed to follow Hezbollah a group that ISIS hates and the Boston bomber This is no different than some Italian kid saying they are connected to the mafia to make themselves sound tough.
Saying it doesn't make it true.