It's work like this that makes me think there should be a "misogyny" tag? Not a criticism by the way. I'm pointing out that work like this of women being intensely dehumanized as slaves, animals, or even furniture has reached a volume of content, and consistency with regards to the tropes employed so as to make it worthy of being categorized in its own genre (JM's art comes to mind). Common themes are multiple women prostrating themselves, extreme body modification, cannibalism, exhibitionism, disgusting or otherwise deformed men, smegma/filthy genitals, collars and chains etc. While this art clearly heavily involves BDSM and snuff elements, its defining characteristic is the world of profound cruelty these elements inhabit. A world where it is commonplace to chain women to bathroom stalls for the purpose of cleaning filthy genitals for example. A world where the status of women is so low that legions of naked women wait on their knees to worship their hideous and decrepit masters for blessing them with a brief and cruel life of sexual slaver as opposed to whatever other gruesome and inexplicable cruel fate most other women experience. It's certainly a unique enough aesthetic to warrant its own tag in my opinion.
I would rather be conservative in adding in new tags. There are already shit tons of tags, not to mention "misogyny" is too broad, practically any doujin that calls a girl a "nikubenki" / "cum dumpster" / "onahole" could easily be marked as misogyny. Even the degree of misogyny has a spectrum apparently. The tags guro and snuff imply an extreme degree of cruelty already anyways.