My argument was mainly against combining both harem and reverse harem into one common harem tag, if we talk renaming one/both tags (as long as they stay separate) i don't really have such a strong opinion on that (even if don't really agree), but'll bite.
Sure, might have started with tags - so lets look at how different sites use them (and tag count):
danbooru - harem 3.6k, 286.
mangadex - harem 113 pages, reverse harem 23.
anidb - harem 784, reverse harem 112.
novelupdates - harem 100 pages, reverse harem 29 (15 pages with both genre harem and tag reverse harem, and somehow also 100 with genre harem excluding reverse harem?)
vndb - this is interesting situation, because we have 2517x "harem ending", no reverse harem i could find, and tag description is about one male and several females. On the other hand, we have 6086 titles tagged as "otome game", and 38 of these also have "harem ending" tag. Won't bother digging deeper into that.
sadpanda uses male:harem and female:harem, but tagging system there is a bit different - almost every character tag will be either male or female. Also harem has a bit different meaning). Still - 14000 vs 4400.
Haven't bothered checking non-english sources here, as we are talking about english.
So we have a foreign word (and not even japanese), with it's original meaning, adapted into english, with very similar meaning to the original, known and understood in this definition by the whole society.
Coincidentally, if we focus only on japanese media, we can also see that this traditional meaning of harem consists of approximately 75% of harem/reverse harem combined.
Why the hell would we add female to it, if the implied context is a) right in huge majority of cases, b) also understood like that by society outside of our chinese cartoon circlejerk?
Sure, name it male harem, otome harem, whatever else - but i fail to see why would we replace harem with female harem. Just for equality? To not have harem as the "main" tag (which honestly it is, both from prevalence and historical reasons)?