I mean I think authorial intent does matter and I think it's pretty clear that for the most part Kenko_Cross doesn't want people to view the monster girls as intrinsically "evil" but they also want them to actually have monstrous features and abilities. But this also results in some issues where so much of the content revolves solely around sex that it makes it hard to actually view monster girls as actually empathizing with humans outside of wanting to have sex with them and some of the stuff they do is just blatantly what a lot of people would actually consider evil and we don't really have any reason to think it's something like anti-monster bias affecting the narrators perception of the actions they're doing. But all that said I don't think that's the intent that the creator had and I'm in the most monster girls aren't bad camp but I think the game could be a good way to make up for those issues considering the MC is directly interacting with the monster girls and not from a mostly third person perspective from the Scholar."The creator said so" isn't exactly an end-all be-all argument winner. Something like that is how you can absolutely ruin a series. For just one example, take a look at J.K. Rowling.
Besides, I don't think anyone likes being told "Your interpretation is wrong because this other person said so". I mean, what's the point of art if not for everyone having their own interpretation of it?
Ultimately, there are two separate sides here, and I have no idea if one will ever get the other to agree. So long as this discussion stays civil however, I see no problems with it continuing. That, or we can just agree to disagree, and leave it there. Either way, I'm fine with it.