>>5672786It's because it's still a very niche fetish. Even furries & futas are more mainstream than monster girls. I know the monster girl community is very passionate about "Muh lore" and stuff. But it's also very small and in an echo chamber online.
Outsiders looking into the MG stuff tend to be squicked out by the creepy sexual fetishes that lie just under the skin of MG fandom. Shit like vore, M-preg, mind control, bloodplay, bestiality, rape, etc.
Just take off your MG blinders and realize that there's not alot of people wanting to fuck a manticore's tail pussy.