The "discrimination" is based on return on investment (ROT), not giving out advertising dollars based on "racial equity."

If there are fewer dollars spent advertising on Black media outlets, it means (A) the increased spending will not result in a like percentage increase in customer spending, (B) the customers in those markets don't need to be marketed to -- they already buy the product, so increased advertising is unlikely to show any significant change in purchases, and/or (C) if there are other markets in greater need of marketing to increase sales, the money has to be prioritized accordingly.

The only color McDonald's is guilty of showing a bias toward is GREEN.