I am quite a bit more tolerant of music genre now, more so than when I was younger and obsessed with one genre etc. but hey we all grow up. As for being told what to play, I would have chinned him. But from experience he might well have had a point with regards to the mixer. I am quite pissed by how someone who cant hold a beat or understand something as simple as gain staging is allowed near a mixer.
You may well not be one of those, so that isn't directed at you.