You are making a key mistake here in your understanding of racism and sexism.
It's not racist or sexist simply to accept there are differences in the circumstances of different races and genders. And, of course, where there is a difference there is a basis for deciding how to act. That can be for good or for bad.
A key aspect of racism and sexism is to put one race or gender above or below another race or gender.
Policies are sexist or racist have to do more than differentiate between races and genders. They have to work to the benefit of one group at the expense of another.
In this case, it appears the internship program is trying to correct an imbalance in the makeup of the tech workforce. It's true the program excludes hetero white males (among others), which is an imbalance in itself. But the idea is that by weighting things in a small way here, a larger imbalance can be corrected.
The idea seems pretty well founded to me. An internship program works in two ways: first, an underrepresented person may get an opportunity to break into tech they otherwise wouldn't get. Then that person serves as a role model, which will lead to more members of the underrepresented group to aspire to tech jobs.
And why do we care if groups are underrepresented in tech? Because tech jobs are generally good jobs. Underrepresentation means there is an underlying economic disparity. Such disparities create tensions that harm out entire society (and everyone living in it).
I'll put it this way: if you see a system that is imposing a meaningful disparity between different races and genders and you insist on maintaining that system by rejecting efforts to resolve it, then you are the one with a racist and sexist policy.
Also, it only makes sense to make decisions on a purely functional basis if you only have purely functional goals. Functional goals are often a high priority, but not the only priority, so it's perfectly reasonable to not make all decisions on a purely functional basis.