There is a perpetual tension in Wikipedia between being a good, succinct overview to X subject matter versus being a repository for information that X subject matter experts would like to see. Editorial policy on WP errs toward the former, and is quite hostile to the latter, preferring that information especially useful primarily to subject-matter experts be located on dedicated subject-matter wikis hosted by other orgs.

Perhaps there is a need for a wiki-based encyclopedia that allows in-depth articles and information by experts, but WP has decided that it is not it.

> History lost forever.

This is putting too much weight and responsibility on Wikipedia and this kind of thought only serves to build up the narcissistic Dunning-Kruger editors/contributors rather than label Wikipedia for what it is: crowd-sourced, with all the drawbacks and caveats thereof.

If there is a piece of history you think is important, capture it someplace else so that it isn't lost forever.

I sympathize with your situation. People are fallible arbiters of truth and relevancy. But why was the fact that this editor was a guitarist have relevance? Was that his/her stated profession (and so by implication you're saying they overestimate their ability as an editor in this particular field of science industry ala Dunning-Kruger effect)?

I think they’re saying the editor had expertise in, and had only edited, guitar related Wikipedia pages previously.