While I agree with your statement but you need to take into the situation into consideration as well they both didn't meet in friendly term. Uno was and still ready to backstab and kill anytime and Enzo is just feeling lust with the feeling of thrill Uno is giving. None of them actually looking for romance here.
Falling in love part is much better when they get to know each other and it's upto them to continue. That's the whole plot here. Also, Uno was sent into honey trap mission so things that are happening he prepared himself for it. Also it's a Mafia x Spy plot where Lorenzo is a total whack in the head. Obviously he won't be acting all fluffy with Uno considering his character.
In the Red candy you saw the opposite portrayal. The ML was total green flag he was normal person like us. The acted within moral conduct. We are seeing the opposite situation in the Bad apple with a more Gray character.
Yeah, rape is first then get to know after. Fall in love like abused didn't happen because it's a fucking mafia x spy!! Idk if he is a total normal person because I don't see a total normal person in this manhwa but hell what do I expect right? This what this story is meant to be, that's the whole plot!! Yes this is a sarcasm. Btw I didn't read the Red and Candy.

The storyline was good ngl, but the sex scenes have always troubled and gave me discomfort. Specifically this chapter, what the mc did to Uno is rape and I am unsure if I would see this story in bright light again. How would the author proceed with this? By my standard a rape is non redeemable and would always be wrong—if Uno falls in love with the mc that would be ironic, because to fall in love with someone who have stripped you with your dignity and abused you is simply a betrayal to your entire existence. If he will fall in love then that would be very sad.