The harem tag was actually only added recently. I really dislike harem manga so I always check ahead of time if it's a harem before reading. At the time I decided to read it, the harem tag was not attached to this manga. I again checked since the invincible girls made me feel a bit anxious about the tag but it still wasn't there. Until the ghoul arc where the big boobed warriors came up and I decided to have a look since it looked like it was becoming a harem, the tag was not there. Quite unfortunate really. It had a lot of potential but now it has become a simple thirst trap for horny bitches but whatever, I'll keep reading for a while and hope it improves.
Look, I understand where everyone's coming from, but it seems like almost nobody read the tags which are Harem ecchi Shounen those are just some of the main ones that you guys don't like if you can't handle it, then don't read it. Oh, yes, his body is physically of a baby his mind isn't, he is mentally a lot older.
Think about it, like this, your older, and have all of your hormones, and all of a sudden, you're transferred into a child like body. You think all of the mental things that you've had before, and past life, whether it be sexual or not, would just disappear.