Responses
It was just in their first meeting though in the novel and its understandable that the webtoon changed it, cuz people aren't going to view him as a proper ml but in the novel, he greatly regrets his words back then cuz he's MADLY in love with Paul. He always thinks that she's cute and gets mad at people who don't see her charms. I like it in the novel cuz Lu actually always calls her "my Paul" (of course when she isn't around).
People probably already said this but just in case, here's some facts from the novels (no spoilers)
So the reason why practically no one viewed Paul as a woman because in the novel it was greatly emphasized that she was ugly. She has a missing molar and a crooked nose (caused by Anino when they first met) which became permanent and can no longer be "straightened".
Lu is very superstitious so at first, he couldn't bring himself to kill Paul for being a virgin since they believe if they killed a virgin, her ghost would haunt them. So he ordered anyone to rape her and then kill her. She got away like in the webtoon but she was naked when she was fighting all of the men that surrounded her. Then again, no one was "enticed" by her body since it was covered in all scars, bruises, etc. Then the story went on after her pledge to Lu.
That time he saw Paul "half naked", in the novel, she was completely naked. There were times during the war when Lu and Paul drinks together, gossip and just enjoy each other's company and sometimes the'd even sleep butt naked next to each other and he'd be seen leaving her tent but no one misunderstood. Know why? Again, greatly emphasized in the novel that she was ugly. ANDDD Lu actually told her to her face that he'd rather sleep with a dirty whore than with an ugly girl like Paul. (she wasn't offended because she was already used to that kind of treatment)
I'd like to say some spoilers but you can just ask what you want to know ლ(´ڡ`ლ)