Let's turn on the logic.
1. A whore is a depraved woman who has sex with many men. Do the nuns do it? No.
2. The nuns have one ultimate goal, which we have not yet talked about in the game, but we will tell you later. And in order to achieve this goal, they are ready to dress up sexy (not to have sex, but to dress up). I can compare it to sexy clothes in a nightclub. Agree, it's absurd when you call all the girls in the club who are dressed sexy "whores". Is it okay to call a girl a "whore" if she's dressed sexy? No.
3. Flirting doesn't make nuns whores either. Yes, they use flirting with the holy father to win him back, but nothing more. Is it okay to call a girl a "whore" if she flirts? No.
4. Girls don't have sex with anyone other than the hunter. But even if they have sex with a man just because they have feelings for him - is it right to call a girl a "whore"? No.
Try to read the story again, and please show me the screenshots confirming that the nuns are "sluts". I see that either you skimmed the narrative, or you misunderstand it. Misunderstanding sometimes does not reflect reality. Send screenshots, I'll wait.