I believe you're being downvoted because you're referring to something that happened over 10 years ago. Not to justify what he said back then, but Brandon Sanderson has grown and changed his views since then.
He is a deeply religious man and his views are rooted in religious belief, the most powerful belief there is. I seriously doubt he has changed his views, he just wisened up to where the wind blows.
Beliefs can change based upon experiences and time. It's called wisdom.
The rate at which public opinion has changed in favour of gay marriage, etc. over the past few decades could have only happened with a lot of people changing their mind. The shift happened way too fast for it to have been entirely down to old bigots dying off.