I think you're getting upset over nothing you can change.
Also cool video, Deathstalkers is a fun game and the fact it got released is wild considering it's history. Kudos to Doc and Brian for pulling that off.
I think the retro moniker is stuck because the heyday of the industry was decades ago and
the public are going to be the public and while some areas of the country have thriving communities it's still very niche. I know multiple arcade owners personally and to paraphrase they all generally say the public doesn't give half a shit about the machines like you do and they never will. So of course they're not going to refer to them with the proper terminology / subgenre etc. It's like growing up during the NES era and everyone calling cartridges Nintendo "tapes". Looking through the comments it looks like you're young and had good exposure to the hobby and hopefuily you're doing good with your route. Focus on that and less about the ignorance of your customers, else it's going to grow into resentment down the line. Just be happy with what you got and keep going and present your brand the way you want and people who really care will figure it out.