In the manga, Demande was evil and reckless, his obsession over Queen Serenity/Usagi was well explained. It makes perfect sense.
But in the anime, the whole thing was cut because he was a overall a reasonable leader and treats his ppl quite well, just got misled by Wiseman. He was not a womanizer nor does he use his female followers' emotion like Rebeus did. I don't think that abduction was well explained nor does it fit his anime persona very well.
Well I'm obviously biased considering I ship Demande/Saphir in the anime and Demande/Usagi was always a major NOTP of mine so I I'm uncomfortable seeing them together in any version but I don't think removing it is the right choice either. Demande's perverse obsession with Usagi is such a fundamental part of his character that it just wouldn't feel like "
him" anymore if you removed it, yes even in the toned-down anime.
Anyways I always got the sense that unlike in the Manga and Crystal where Demande truly did see Serenity as nothing but a conquest to conquer, in the anime and musicals he only got so fixated on her after that glare she gave him because it triggered his insecurities about himself and he was determined to prove to this all-mighty Goddess that he
was worth something, and was just as much as a human deserving of love as she and the rest of the Earthlings. You have to remember that in the 90's anime, and especially the old Musical's continuity, the BMC were an oppressed group of people and almost considered another race, their ancestors were literally banished to a whole other planet just because they refused the Silver Crystal's cleansing. Now why would they even need to be "cleansed" in the first place? (Especially since the whole 1000 year life-span granted by the Silver Crystal doesn't exist in the anime's continuity) Well I like to headcanon it's because they're descendants of those with Youkai or Demon blood, it would explain why they all seem to have inherent magical abilities and Demande even has that 3rd eye and such (Koan herself also resembles a Nekomata Cat demon) How would they even be able to have such supernatural powers and abilities if they truly were just the descendants of ordinary human beings from Earth? And you can't say that living for dozens of generations on a foreign planet like Nemesis imbued them with those powers, I'm sorry but genetic drift doesn't work that way.
The anime never makes mention of them being given those powers by Wiseman and the Dark Crystal like the manga does, so my theory is that the "cleansing" NQS forced their ancestors to go through was to rid them of their Yokai blood and turn them fully human, naturally they viewed it as discriminatory and refused and the populace had begun to grow fearful so NQS had no choice but to send them away.
I like to think most of Anime and Musical Demande's obsession with Serenity stems from this inferiority complex. He and his people are already viewed as monsters, so seeing that viewpoint being reflected in the eyes of one that's supposed to be the paragon of purity herself probably triggered something in him and made him want to force Serenity's eyes to see him as a man rather than a monster, perhaps he felt that would be his own personal "cleansing." Remember also in the musicals Demande seems to be particularly obsessed with purity, so much so that he even has his very own song centered around it, "Innocent Demand!" His obsession with winning Serenity's love simply stems from a desire of validation and acceptance over what he perceives to be his clean, inhuman self so I think in that sense his obsession with her still makes sense even within the anime, it's just given a different context compared to the source of his obsession in the manga, a "purer" motivation if you would.
Plus I'm pretty sure the "R" in the season stands for "Romance" so it would still make sense for Demande to be obsessed with Sailor Moon in the anime, if you really think about it the entirety of the season is focused on the dilemma of romantic triangles. You have Ail and En that are a couple but are crushing on both Usagi and Mamoru respectively, (yes I know that was just a filler arc but it's canon at least to the anime's continuity so it counts) Koan harbors an unrequited love for Rubeus while Petz has one for Saphir, Esmeraude is crushing hard on Demande and it's heavily implied Saphir has more than brotherly feelings for him too, Usagi and Mamoru have that whole Break-Up arc drama etc, so why
shouldn't Demande be obsessed with the Queen here? This is pretty much
the season for dealing with romance, so it fits thematically.
One last thing though...
"Demande doesn't have a temper in the 90's anime"
This is flat-out untrue, he might be not be as ruthless as he is in the Manga & Crystal and quote-unquote "a better person", but he's still just as temperamental and reckless as ever in the anime. He loses his cool and strikes Saphir in anger
twice and we even see him get angry at Wiseman a couple of times (the scenes where purple energy is building up behind him, that's supposed to be an indicator he's about to lose his cool). He also shakes Sailor Moon hard the 2nd time she resists his hypnosis and refuses to submit. He's not some perfect Prince Charming even in the anime, not even close.