Every number is a number, including zero. Therefore some number of members of any given group have been discriminated against. Therefore any group is indeed discriminated against. You can't argue with objective mathematical proof.
Slightly more seriously, if someone is discriminated against for being part of a group, you don't get to appeal to the fallacy of composition applied to all groups in order to claim that there is no discrimination against that individual. Yes, yes, you're not actually writing out that argument, you're just leaving its ingredients lying around next to a naked flame.
Do you realize how absurd language would be if what you claim is true? For example:
- Is is true latino men are discriminated against when applying for florist positions?
- Yes, it happened once.
Literally any group would be "party discriminated" in every possible scenario according to how you define "at least partly".