I think it's just a matter of time. America is becoming more heterogeneous and more tolerant every year.
Wrong. Dr. Umar Johnson, who is one of the most beloved Black commentators disagrees with you and the Democratic Party. A lot of Black Democrats think like him, aren't no different than White Republicans.
This is your party, this is what your party is going to have to get votes from in South Carolina, etc.
I have no idea who the heck this Umar guy is, but blacks are not in general against interracial marriage. In the most recent vote repealing the anti-miscegenation laws (MS, 1987), repeal won by a narrow 52-48 statewide but the margin was much larger in black parts of MS. People back then were also making the same claim that you are here.