There is no tax break in the US for hiring certain groups of people (at least in regards to race and ethnicity). This data is requested for reporting purposes only. This is how companies can release "diversity reports" or answer questions when EEOC investigators start asking questions.
I seem to be lucky in that I haven't directly seen any racist hiring policies. But, then again, I've only worked hourly retail jobs; for all I know, the higher you go, the less likely a hispanic man is to be hired. And it doesn't help that there's so many variables to control for--as other comments stated, it's filters all the way down. As an example ffrom the entertainment industry, I have never owned a computer powerful enough to handle both running a recently released game and recording footage of the gameplay, which means that my dreams of becoming a Youtube Star are rather limited. And don't even get me started on capture cards. The rich kid down the block can afford it because his parents buy it for him; my parents don't, and the reason for that could extend as far back as the lessons my grandmother learned when she had to work her way to the top of the Georgia Pacific packaging plant where she made her living.