Race mixing is the genocide (in the literal sense) of actual racial diversity.Racial diversity is not intrinsically evil, so whether it is good or bad is a matter of civic wisdom. Orthodox are free to have opinions on this.
However, there are limits. If Orthodox were to oppose, for example, a mixed race marriage between two fully Orthodox laypeople, that would be wrong. On the other hand, support for critical race theory is also incompatible with Orthodoxy.
What if such a marriage is the result of globalist brainwashing? There is, in my opinion, a certain implemented hatred for the own ancestry in interracial marriages. I think, it is insane to desire that your kids look wholly different than your parents and grandparents. I am not advocating for racial purity, in the sense that a Germanic person can only marry another Germanic person, but a Japanese and a Congolese mixing just seems to me to be the willful subversion of God's creation. Not that the child of such a relationship is in any way less. To me such is a babylonian-masonic-globalist genocide of actual racial diversity. To conserve the different races and ethnicities (God's creation) should be considered the actual "anti-racism".
Who is promoting race mixing? The same people that promote drag queen story hour and abortion. But even Christians have been brainwashed into thinking that someone categorically opposing race mixing is some kind of Nazi, although that person actually cherishes the different races and wants to preserve them.
I noticed, that is my observation, that today even more based pastors and priests are rather boomerish in their political and cultural views compared to John of Kronstadt and Martin Luther and other notable figures from the past.
How did the subversion of American society start? It stared with "Don't be a racist", then it was "Don't be a homophob" and now it is "Don't be a transphob." I see an obvious slippery slope at work here.