There are several possible reasons:
1) He's one of those people who don't want to be told what to do.
2) He's received too much misinformation.
3) He has genuine concerns about the effects of the vaccine and as a young, healthy athlete, he feels he's in a low risk group.
Whatever it is, it has to be pretty strong for him to give up $45,000 and to endure all this scrutiny.