I find that attitude baffling, don't you? But you do encounter it sometimes. Glenn Gould quite famously claimed to hate all music written between 1750 and 1900 or something -- but he still extensively performed and recorded it, so he must either have been lying or really wanted the money.

Something one comes across a little more often is a prickly attitude when you tell a performer or composer that you thought their piece was "pretty" or something, which can be taken as pejorative if something more along the lines of the Kantian sublime was intended! Maybe that's what the conductor in this case meant.