It's mostly because people who enjoy mature romances come here to read a mature romance
This is just a high school romcom disguised as adult romance so the rating drops on being clickbait
Take "Telework Yotabanashi" and make it seem like a HS romance + slow progress and you will get this, this is supposed to be a seinen but it doesn't look mature.
that's my take on it, but I'm still enjoying the ride nonetheless