It existed, but it was much more rare. Yes, slave owners had sex with their slaves and produced Mulato's who were mostly house slaves. Yes, across the Middle East you do have a mix of races, that goes back many centuries. 99% of Europeans didn't come into contact, in a social sense, with non-Europeans until the invention of jet technology.
"European" isn't just one race, nobody from Europe calls themselves "European" they call themselves whatever culture they actually are, that's an American thing because everyone is a random mix of races....your premise is a flawed cope. If you meet a person who resides in the continent of Europe and ask where they are from they or what their culture is they don't say "Europe" or "European".
Regardless that can be applied to every culture on the planet not just Europeans, I don't know how you found a way in your head to apply it specifically to "europeans". If anything it's the opposite, Europeans were race mixing before anyone.
In your example of the Middle East it was taboo to marry outside your village, let alone your race, and that is still true today preservation of culture has an incredible amount of importance.
None of these race debates interest me I'm not here for that garbage but if you're going to say things at least make sense....