It would be incredibly easy to apologize and have it over with.
He's either too prideful to apologize to for his "joke" and is deciding to minimize discrimination against gay people (gay kids in particular) while he's at it, or he actually has bigoted views. Neither of which are a good look. Neither would be something the entertainment industry would want representing them at an awards ceremony. Instead of just quashing it and having a feel good learning moment, now he's the victim because people dared to ask him about things he's publicly said before. He was acting like a child 11 years ago, and he's still acting like a child today.
He's a multi-multi-millionaire with a huge public voice and will continue to be one and continue to star in blockbuster movies after this. He's not entitled to host the oscars. He's not entitled to never be questioned. People acting like this is a trial that will leave him penniless and/or in jail, and not just him missing out on a gig, need to step back and look at what this situation actually is.
I'm sure his Joe Rogan appearance will do big numbers, though.