Discrimination was right because the people I chose were competent.

If I were to say decide I want to deliberate a ginger hair owned car garage, and then justify this afterward by the fact that they either did a good job and/or were one of the ginger garages known to do a good job, therefore I was not unfairly discriminating against other garages because the people I chose were competent?

If you draw a conclusion based on unsound premises (e.g. that ginger haired owned garages do the best job) then your conclusion is unsound not invalid.

I think, however, you are suggesting something else - that the person prefers to use ginger-haired owned garages (reason unspecified but could be prejudice) and wants others to believe the choice was based on competency and not prejudice.

I think this is a disingenuous use of post hoc rationalization.

If the person continued to exclusively use ginger-haired owned garages because they now believed they had reason to conclude that all g-h owned garages will do a good job then they might be using either the fallacy of composition or hasty generalisation.

Exactly what is the question?

Perhaps post hoc rationalization . In this context, not really a fallacy but more of a biased way of thinking OR a deliberate lie.

I'm not sure what the fallacy name would be, but it it fallacious to assume that a non-ginger person would not be as good as a ginger one.

It's roughly the equivalent of saying "oranges are good, therefore apples are bad".

I'm guessing that would be a non-sequitur (invalid conclusion).