Probably because, within the US, minorities form a pool of low cost labor in competition with white labor. This is somewhat true in the middle class, where minority college graduates tend to make less money than white grads competing for intellectual and skilled jobs. This is very true in the semiskilled labor market, where immigrants are paid less and are in direct competition with white or established minority labor.
When you have social dynamics like that, you're not going to appeal to minorities by indirectly attacking one of the most prominent minority groups in America (and the world, if you think about it) and attacking low-cost labor in general.
MBS:
>IMPORTS. Who makes 'em is irrelevant. What they
>get paid is relevant.
The problem is that, due to colonialism (and slavery), there's a strong correlation between color and poverty, on a global scale. Businesses exploit this inequality. With globalization, businesses can look not only at global disparities, but local conflicts that lower labor costs.
This happens even in the US. Recently, my mother's workplace was bought by a Japanese food conglomerate, which has been actively eroding benefits and rights that were secured by the union years ago. They're taking advantage of the large number of Latino workers in the LA area.
So, now, you have Japanese owners bringing in Anglo management to exploit Latino labor.