I think there's a social custom in the community, that relates to "you can be your own expert." That is, opinions are weighted by some function other than technical knowledge and expertise, such as status as a musician, enthusiasm, cost of equipment owned, etc. Nobody wants to come out and say: "You're imagining things." Technical discussions often erupt into flame wars.
And there are some areas where things are probably measurably different, and it boils down to taste, but the measurements are hard to do. I can hear differences between the two instruments that I own. Does that mean I'm bonkers?
At the same time, engineers who aren't immersed in this field tend to be polarized into two extremes: Some are audiophiles. Others simply dismiss everything as audiophile nonsense.