If a story involves Bitcoin and every crypto shyster on the platform links their wares in the comments section because it’s “relevant” does that excuse their behavior?

I’m sorry, but “relevance” is far too often in the eye of the linker. One can link someone else’s story, I think that is always fair (when “relevant”) and one can always ask permission to share a link they believe relevant (like asking for an invitation). Otherwise, unless an author invites others to share such links, I too believe it to be a violation of etiquette.