They are indeed genderless, but it's evident that they are male-coded, as in, they are designed to look more like boys than people in-between. So It's not that surprising if readers think of it like that. Besides, it's not uncommon at all to use methods like these to safely add homoerotic-subtext to stories that would be censored of forced into a niche market otherwise. I don't think this is what was intended in the case of this manga though, I'm only saying that it's not unthinkable other people would get BL vibes out of it.
It's not too different than how the gem-people of steven universe are genderless but are designed in a way that has the audience perceive them as female. Same for Houseki no Kuni characters (at least for the anime adaptation's design).
But in this manga, all the children's romantic interests are grown men.
In my opinion, it would be more interesting to have more diversity in romantic interests.
I keep seeing tags and comments saying this is a yaoi or shounen-ai. Like wha-