That's only a conservative estimate of genetic isolation though.  In America, plenty of Caucasian and Africans live near each other, yet the interbreeding between groups is something miniscule under 5%.  Since white genes are recessive, the white race would not exist if this ratio was higher.  Due to this, whether your Marxist mind acknowledges it or not, if you advocate that everyone on earth interbreed with each other with no regards to race, you are in fact advocating white genocide due to white genes (and Asian) being recessive.

It's pretty easy to verify this with virtually any interracial relationship that exists.  Take Heidi Klum for example.  Here's her with two of her kids, each from different fathers.  She's supposed to be a supermodel, yet has passed along virtually none of those supermodel genes onto one child, while clearly having done so for the other.  This is because white genes are recessive and it's hard to even tell the child on the left is related to her at all.