I can relate to it. I'm so exposed to harem in shounen mangas that sometimes, if a girl is introduced in a certain way, I can sense that there will be harem or she will have a hots for him. It's uncomfortable because you'll think in the back of your mind if this is how the author or the target audience views girls in real life, but also, there is this feeling that a certain female character might ruin the story for you. I can only think of few female characters that are treated as characters and not as a plot device, a love interest, or a fan service. So, while it can be annoying to read comments about wanting to not have romance in a shounen manga, I can understand the sentiment.
Yes, I hope this one won't turn out like that. I've had good stories turn into harems or something. Hopefully this one will stay safe.
Yes this is also how I feel.
they're not mad at actual human girls
most people are mad at shonen writers/mangaka who build up a good plot with a male MC but prove they know jackshite about creating female characters which says a lot about their sense of empathy. they only know how to frame them sexually, not as an actual human being w/c ruins story immersion.
don't reverse the narrative here.
of course there are incels who literally can't tell reality and fiction apart and project their anger from a harem character (who is often a badly written pixie dream girl) to actual girls and women. imo they need to be segregated from society
but majority of people who react badly to girl side characters being introduced are those that have experienced the jarring disappointment of a story they like being marred by tired, gross, sexist stereotypes that add nothing to plot progression. for girls who love shonen i'm guessing it's even harder.
welp, with all that said
i think it all boils down to how much you trust the author to handle character development.