Well no, not really. There's evidence of humans having interracial relationships all over the world and throughout history. It's neither modern nor against human nature.

There had to have been a way we developed so many skin colors and ethnicities and variations within race in the first place, and that's through all kinds of patterns of genetics mixing together after evolving from monkeys. So if you want to come in with the bullshit "you're fighting human nature" because you're too insecure to be a patriot without actually wanking off to alt-right feelies, I dunno what to tell you.