As hard as it may be to believe, lots of pilots outside of the airlines are required to wear pilot uniforms when they perform their jobs (usually charter and fractional, but some corporate too). These pilots are often repositioned using the airlines, and are usually flying on expensive full fare tickets (usually purchased a day or two in advance). They don't need to explain their actions every time they fly on an airline.
I'd be pretty pissed off if you got in my face about it while I was minding my own business, doing my best to forget that I'm stuck in the back of an airline just so that I could get to work or go home. If you were pleasant about it, no problem. But demanding? Your boss would probably be getting a call.