[user104658]

Originally Posted by GoldHeart

But if you want to fly abroad on holiday you HAVE to be vaccinated anyway, why is that different when that's also MANDATORY ?.

The key is "if you want to fly abroad". Flying abroad for a holiday is not a necessity. I guess that's sort of like saying "if you want to drive a car, you HAVE to have a drivers license". That doesn't mean having a driver's license is mandatory in everyday life.