Why is compulsory social security unfair to migrant workers?

Why is it unfair? Not letting you join social security is the biggest injustice. If you lose your land, do you want to spend it in your own hands, so that you will have no old age to support in the future? No Country for Old Men, do you want to put the economic burden on children, society and the country?

How can you be so selfish? You have to be forced to be selfish and ignorant. There is no other way.