You are absolutely correct, most people want to work when they can, but look at it from the government's perspective, if they see a severely disabled person in his 50s with zero education, zero knowledge of the language wanting to migrate to the country, what they see is just an expense with few prospects of being able to contribute enough to offset the cost of treating/managing his disabillities.

He may be an absolute genious, but that is not known at the time, the government also must consider that any resources spent on this person can't be spent on someone else.

So in this case the financial argument is clearly against accepting the person, based on the information the government has, the person should be rejected.

In a purely financial world, that would be it, but luckily we live in a world with more incentives than purely greed.

Taking in the person will generate goodwill in some parts of the world, that might be reason enough to do it, or perhaps the person has valuable information that could also be reason to let them in, perhaps this person is part of a political party in his original country that you want to remain good friends with, then this is an excellent opportunity to show support.

All of this is extermely cold and calculating, I absolutely conceede that, but a government can selldom afford to let feelings dictate policy.

Even governments showing compassion do it for their own gain, it's good PR!

This is reality, and it is better to face it and deal with it than to fight with an immaginary entity.