[AngusThermopyle]

A prop is a prop, and a dealer is a dealer.
A dealer who is playing while on the clock could be viewed as a prop, but most players would view him as a dealer.
Most players understand that a prop is just trying to make a living and should play however he thinks will bring him the most profit.
But when they see a dealer playing, they see someone who depends upon tips from players such as themselves for their living. Even though they know check-raising is part of the game, they feel that coming from someone who scowls at them when they forget to toss a $1 tip, it is a poor public relations move.
I know dealers who refuse to play in their own club for that reason.
You emphasized the fact that this was a "prop" in your post, while I think the guy's objection was that it was a dealer.