I did not create the tag breasts. However, I do subscribe to tags from dozens of different Stack Exchange sites. If tags are removed arbitrarily, on a whim, I may not be notified when new questions on the topics that I find interesting are posted. I am not the only one who subscribes to tags.
If the tag breasts violates some guideline, why was the tag orphaned only now?
The moderator in question did not provide any reason for the removal. If a guideline is being violated, then why wasn't the relevant excerpt posted on the edit summary? How can the reader not acquainted with the guidelines of Biology SE distinguish effete prudishness from blind adherence to seemingly arbitrary guidelines concocted based on years of accumulated experience of moderation?