The scarcity in Europe (at least the two countries I'm familiar with) comes from a standardized test. If you don't do well on the test, you don't go to college.
There was a study on one of the most selective school in France and actually diversity of background has gone down in the last 20 years. Europe is highly politicised and it was always about selecting for ideologically compatible behavior. Otherwise education wouldn't need so much government intervention/support, even if said education would be paid for by the taxpayer (everyone could get some amounts of credits, that they could spend on their institution of choice).
For what it's worth, the USA isn't unique in adapting admissions to reject an unwanted minority. The most interesting mechanism has to be Moscow State University's Jewish Problems: https://arxiv.org/abs/1110.1556