1) they knew they would be fighting a losing battle having him come out and try and be the face in front of this crowd, so they let him acknowledge the boos and have him play sort of heel without doing anything that will hurt his babyface position in the long term. He didn't insult the crowd, attack a good guy, etc

2) they are moving towards the heel turn. AJ being his first challenger is intriguing, and you have to imagine one of them is turning at the PPV. And I'd bet that Bullet Club/Balor Club/Bullet Proof may have something to do with it.

Regardless, Roman gets an A from me tonight. THIS is the character he needs to be. An absolute bad ass who only needs to say a few sentences to get his point across, and other than that is just looking for who is gonna be next on the list.