Ah okay, so your main stance isn't whether URM is good or bad but that it is discrimination and should be labelled as discrimination?
Yes, if you think about it, everything in life is discriminatory. There is never a fair system. Med schools are discriminatory towards people who study better, learn faster, and are able to juggle their time better. And a lot of these traits are linked to genetics, social environment, and the income level which we are born into.
If you have a race between a two legged man and a one legged man and the referee gives the one legged man a 5 meter head start, is that discrimination? Yes, it is, since everything nowadays can be technically labelled as discriminatory, but since things were inherently unfair already, then it can't be helped. And what if, if the two legged man won, he was more likely to use his money to buy a car while the one legged man (who can't drive) was more likely to donate money to charities that support people with physical disabilities?