Wow. That wasn't my experience at all and I've been to two of those talks now. The first one was in guitarguitar in Birmingham and Bernie Marsden was there to play a few tunes. He was really engaging and funny, the crowd asked some good questions and were a pretty decent mix of ages.
The second one was down at Peach guitars and he spent some time pulling different guitars off the wall (not just prs) and explaining what he looks for when testing guitars at the prs factory and when he's shopping himself. There was no ragging on other brands at either event.
Both talks he hung around after chatting to people who stayed on, Bernie Marsden was actually pretty funny.
I also know a guitar builder who attended one and when Paul found out he had one of his guitars with him he asked to see it and spent some time going over techniques, material choices, finishing etc.
Anyone I know whose met him have always said he's happy to chat about other brands and not just his own. It's weird that your experience was so different, off night I suppose.
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I covered mine in envirotex so it doesn't rub off through playing.