Casteism

I sometimes wonder what is this caste system that we were born into. Is it good or bad, is it's influence diminishing. One thing is clear that untouchability is plainly wrong, there is no issue with that. What I am talking about is when well-educated , well-settled men look for brides. I have been shocked by my personal experiences when my friends have only sought brides from within their castes. They dont even bother to look for girls outside their caste. I wonder why is this, when in this age of globalization people travel distances to study and work but when they want to marry , they want one from their own caste. Love marriages are a different matter, I want to know why can't WE ask for "arranged inter caste marriages".