Nah....this happens a lot. You point out how awful and illogical people's arguments are, and they start to back peddle, and deflect by claiming they never said it. Several people in this thread raised the idea of white supremacists disfavoring IR dating as some sort of support for why blacks shouldnt do it, and in general a great many of posters here claim that whites are "inherently" evil, and also believe other racist theories about how all Asians and hispanics hate blacks and dont date out (those groups actually marry whites at far higher rates than blacks).
And to correct a factual error in your post, no, Amercians do find interracial dating to be 'commendable'. Whenever polling agencies ask random people about IR dating/marriage the responses are overwhelmingly positive and the approval rate for IR dating in this country sits at around 90%. You couldnt even get 9 out of 10 people to agree that the sky is blue.
If you believe that you can accurately tell whats in a black man's heart based on the color of the skin of the woman he fell in love with, without knowing a damn thing about both personally, then perhaps you should check your own racial biases rather than being so concerning about who or who isnt "pro black".