I think the seme simply sees the dresses as cute on the uke, it's not a matter of being gi...

I get you but isn't it strange how the mangaka referred to the uke like girlfriend but he is a boy it kinds of feel like he/she denied the sexuality of a guy in a gay relationship like trying to seem the most "NORMAL" possible?

This is a perfect example of a social experiment. It is not the mangaka denying the uke's sexuality, it is readers denying the uke's sexuality because they cannot get pass the uke's physicality and relationship dynamic of the main characters, that they are not conforming to their gender schemas. And I'm not trying to be rude here, I'm really just making an objective observation based on the reaction of all the people that object to how the uke looks because his physicality or their treatment towards each other (mannerism, dialogue, etc.) does not conform to the sex-linked characteristics all of us have been taught through socialization since we were children. That is the real travesty, that most people don't even understand their own reactions, why they feel the way they do. Again, it is not the mangaka trying to "normalize" the uke, it is readers are judging the manga and characters based on their own concept of what is "normal". The bottom line is what may be strange for me may be completely ok for someone else. That the seme calls the uke his "girlfriend" could be due to a myriad of reasons that have nothing to do with gender "normalization", something specific to their relationship, which is a realistic extrapolation of real life couples, meaning that real life couples have unique aspects to their relationship, whatever those aspects may be.