I would say it depends on the persepctive.
Many people prefer to be the MC and build an harem. Un ugly boy gets a huge Dick and all girls in life fall over him. None of the girls even dare to look to other guys, the world spins all around him. While the graphics are nice and everything I don't like these stories, as these are way out of reality.
I prefer it, if its a bit more realistic to the real world. And NTR gives you that option.
When I play NTR games my mindset is not that i am the MC and get cucked, but that I am the other guy who steals the girl from the MC to just wittness the cucked persons POV before I get his girl. It happens that you try so many things to get a girl, but in the end someone else gets her, be it cause he is better looking, more athletic or blackmails.
Basically I am the NPC that gets the girl.
It's nice to play not just a nice lovely harem game where no matter what you do you get all the women in the world but sometimes lose or struggle or have an actual enemy (in NTR cases for me its the MC as the enemy).
But thats just my sight
Thats why I like to say to the NTR haters: Just play the game and imagine you are the guy who steals the girl and not the MC. That way you have your harem again
Just another perspective!