I don't see your banned substance analogy as being comparable. There, we're talking about a player getting suspended and hurting the team for putting a substance in their body. With vaccines, we're talking about someone choosing not to put a substance in their body. If they have to put a substance in their body it essentially makes it mandatory for them. If we don't believe in mandatory vaccines for citizens it doesn't make sense to want that for professional players. They're normal citizens too; it's still a job for them.