I despise it and am also glad that it was removed, but I do get it.
Chibi-Usa wanted to grow up and be a lady. Part of being a lady like her mom is having is a man, and her mom has Endymion.
Basically, she wants to take her mom's place.
On a side note, it's weird, though that they removed it given that they amped up the Chibi-Usa/Usagi rivalry by contrast. In fairness, this does make Wiseman's vision have more impact (suggesting that despite learning Chibu-Usa is her daughter, some part of Usagi has lingering jealousy) but on the other hand, it creates a lot of buildup to largely nothing.
Chibi-Usa does have a crush but Black Lady doesn't seem to share those feelings.
Wiseman tempted Sailor Moon with a vision of Black Lady kissing Tuxedo Mask and being with him, but it wasn't real. The closest we get to a crush is Black Lady being surprised that Tuxedo Mask would step in front of her blast towards Sailor Moon...but there is next to no evidence of romantic feelings. Black Lady hated Tuxedo Mask as well.
Heck, in the old anime, the closest male she physically got to (other than Wiseman, of course) was Prince Demande for one brief scene.
*Sigh* This is why I dislike the Black Moon Arc. Chibiusa is such a flipping loon in it, even in the manga. She doesn't *act* like a kid raised by Usagi and Mamoru or even sharing their genetic traits personality wise. Like pulling a gun on her mom and demanding the crystal. Was she raised by gangsters? (Admittedly, the idea of Chibiusa being kidnapped as a baby and raised by the villains is a cool idea.)
Though I do wonder of it's a bit of a culture clash. Japan has never had as much of an issue with incest.
Yeah that was never a good look. Honestly that whole subplot with Serena being jealous in general was not a good storyline for that season. Esp when we flash forward to SuperS and she has a crush on Haruka.
Though Usagi acts like her mom with the tucking her in and reading her bedtime stories. It's so cute, they should've explored that more. Maybe Usagi trying to act like the way she thinks a mom is supposed to and messing it up.
Alpha males with expensive sport cars are in high demand and there aren't enough of them for every woman out there. In Naoko's vision of the world, it's better to have sex with your own father (Mamoru), a criminal (Nephrite), or even somebody without a penis (Haruka), than to ever end up with a pathetic beta male who can't afford a Ferrari or Alfa Romeo.
Wise Man basically twisted all of Chibi-Usa 's desires which was why she kissed her dad as Black Lady. Also Mamoru had no agency while he was being by an evil grown-up version of his (future) daughter.