I'm not sure it would be as easy as that. I know students can easily get out of getting vaccinated by telling the school they can't for religious reasons. Or at least they could when I was in school. So I can WDW being wary of implementing a rule like this and then having people claim they're being discriminated against for religious reasons.
I don't know a whole lot about the laws when it comes to vaccines though, so maybe someone more knowledgeable about whether this would be allowed could chime in,
Well, to be honest, they should be excluded as well.
If I couldn’t eat a certain type of food for religious reasons and a restaurant only served that type of food, no one would expect the restaurant to change their entire menu to cater to me, I would need to find a different restaurant.
This pandemic is so much bigger than people with their own individual beliefs that for the good of the masses, those people that are willing to participate in something to protect their fellow human (getting the vaccine) should be rewarded. The rest, for personal, religious or other reasons who don’t want to get it will have to wait until the numbers of Covid drop substantially after the rest of us get the vaccine before they get to enjoy a theme park.