The quotation of questionable source that advocates "never learning from people that always agree with you" springs to mind.
IMHO audiofoolery and audio myths permeate the industry, but scammers and conmen/women across all walks of life have existed since time immemorial. That said; I don’t support berating anyone for their beliefs. Obviously any intent to cause harm is excluded.
If a friend discussed buying "audio rocks" or something equally inane, I’d gently caution them, but if they persisted; I’d back off immediately, as it’s their money to spend as they wish.
I’m also a firm believer in diminishing returns and cannot personally discern sound quality improvements (differences maybe) in equipment after a certain price point. BUT: That’s me. If others wish to chase "perfection" so be it. I will probably benefit indirectly, via trickle down technology anyway.
Exclusivity and cliques are also a big turnoff for me. Can't stand that gibberish. It's synonymous with inbreeding.