Pretty sure that was just showing how momo and his mom were coping by convincing themselves it was malicious instead of a desperate cry for help, the past was being told from momos perspective and he immediately contradicts it after when he cries and admits he didnt want to be raped. Then a chapter or sum later he says that doing that with those men and everything he did was because he wanted his mom to really look at him. It only looks like their pushing the narrative him stealing those men bc thats how MOMO chose to see it bc he didn't wanna think about how in reality he was raped by a bunch of adults because he'd end up breaking down like he did. If you wanna understand it better reread a the pages once or twice, it helped me.
I love all of harada’s works but the way they’re pushing this narrative that momo seduced the mom’s bfs is so weird