Well, no defending or criticizing, but she doesn't fuck a lot because of a spell, she fucks a lot because she finds it "fun" and it's repeated several times, like in the first scene with the evil wizard, she doesn't doubt for an instant to go fuck him after he casts the compunction spell for her to come back and after having sex with the futa magician she goes back to Malloty who uses another futa spell (I think some patreon with fetish futa released a bauble on that update hahaha). But to sum up this spell parade, one makes her unable to have a desire for the MC (trying a justification for her not to have sex with MC, kind of like the mother's characters in incest games, the ultimate prize) and the other is the compelling one that the Wizard casts when she goes to "investigate". But nothing makes her find random sex fun except the "half fairy" one.
Because the game was originally created to be a male protagonist, but the DEV saw fit to put one of the LI having MUCH more fun than the MC, folks complained about the "NTR" and in the hope of calming the nerves tried to put it as a protagonist multiple. But even though Lucy has plenty of screen time, you can't choose anything that changes her personality or path, Example is when Mallory asks her if she enjoyed the sex with the futa mage, you can choose to say you enjoyed it or "lie"(you don't have a choice to say you don't like that fuck and stop it), and even "lying", Mellory will still charm the futa spell and have sex with her.
Many things do not make sense here, the DEV has many opportunities to branch the game to give choices and expand its audience, but he, or does not want to or does not have the capacity for it, an example would be this part of all futa content, if he created a variable for this choice that blocked the other futa scenes and changed to only lesbian or even avoid this type content, I'm sure it would please some whom not like the futa content (me as one of them). In the third update he seems to be learning or wanting to improve some things, he gives us the opportunity to stop Rose's hunt on Elli, if he did that for all the rest of the contents that are not "necessary". to tell his story, he could reach a much wider audience.
But well, I'm sure he's making an effort, I saw a huge improvement between the first two versions and this last one, although I still think it's a mistake to close Lucy's route before making a "redemption", but who knows if she plans to open another route for her after she "heals" herself (who knows, maybe it's the real harem route). But the game has an interesting backstory, a pity that Dev wanted to "innovate" with this "equality" thing and ended up kind of wasting a good story.
Remembering that all this is just my opinion and I'm not here wanting to make the DEV write the story according to my tastes, is only exposing my opinion and who knows to add something to the story he wants to tell the tastes and opinions of him.