Discrimination at least in this case means attributing value to a person (seemingly) belonging to a certain group. The word you're describing is called choice.
You do not date X bc you prefer Y (higher value). You do it with everything... we do it. It is just how things are... that you choose one over the other makes the other the not chosen side of the thing. So yes, in some way you can see that as discrimination (even if we do not give it political meaning, it is still)