Originally the rich would buy the poor as slaves, or feel somewhat sad if they starved.
Over time, the goyim picked up the idea that the rich need to help the poor. They got the idea from us. Also we never had strong central institutions (even kings of Beis David were far from absolute).
The Christians combined our ideas of charity with the Roman idea of a powerful government, and you get a powerful government that gives lots of charity with other people’s money (while governments get money from many source, taxes seems to be the easiest way to get hands of money).