I think there is a huge misunderstanding here. Any tag is perfectly fine unless it's part of the very few topics Medium clearly doesn't boost, and that's been clear in the guidelines since day 1. I know, cause I read it with great interest. I have plenty examples of stories boosted that have very niche tags. So do other authors from what I can see.

The misunderstanding stems from Tony adding an additional requirement for his pub and that's entirely within his remit to do so, so do many other editors. I think the conversation you wanna have is with editors and pub owners.