i'm no expert but i think it's like a tech ethics thing: this is a super crude example but, if you filled out a sign-up form on a website and indicated that you were a minority or make less money, some programmer might have added logic to the form to present a higher sign-up fee for people who indicated those factors, which would be discrimination.

another example could be that prices you see on Amazon are set depending on your personal info or where you are location-wise, etc.