Depending on how you tell it, Beauty and the Beast can be a pretty problematic fairy tale. Girl is locked up with a beast and develops Stockholm Syndrome, falling in love with him and curing him of his monstrous ways.
In its previous Beauty and the Beast episode, Once Upon A Time did a good job of working with this. Rumplestiltskin made a bargain to save Belle's kingdom if she agrees to go and work for him. She's scared of him, but (and correct me if I'm remembering wrong) he's nothing more than a bit testy with her. She quickly gets to know him, sees beyond his appearance and falls for him.
Unfortunately, this episode decided to expand upon the "beast" phase of their relationship, making explicit that their relationship is messed up at best, and deeply disturbing at worst.
In Skin Deep, we can imagine that Rumplestiltskin is perfectly nice to Belle from the beginning. She expects him to treat her horribly, but his attitude is very much "this was a deal we made, there's no need to be cruel about it." At the start of this episode, we see Rumplestiltskin treating Belle like more of a slave. She's incredibly miserable, sleeping in some kind of dungeon in the same dress that she wore when they made their deal. In a not-too-short space of time, she hears and sees him attempt to skin a thief alive, and although he doesn't kill her (as she expects) for letting the thief go, he hardly treats her kindly. Yet although she's horrified by him, she insists, again and again, that there must be some good in him, and even hugs him when he lets Robin Hood escape with his life. At this point, she just seems naive and frankly ridiculous, and her growing affection for Rumplestiltskin (because he DIDN'T murder someone he originally planned to skin?) is troubling to say the least. We go from an unlikely romance story, with a few problematic elements, to a story where the love of a kind, patient woman, who insists on seeing the good in everyone, can change even the most psychotic of killers. Even if he is abusive to the point of slow, bloody murder, a few reasonable words and a little bit of faith can save him.
Rumplestiltskin has always been a somewhat morally grey character in the show. He'll strike deals to do whatever you want, and horrible consequences may occur, but he will warn you about the consequences before you begin. He always seems like he enjoys making deals and helping others inflict chaos on themselves more than being a ruthless killer for the sake of it. Yet this episode seemed to up the pointless brutality, as though to demonstrate how much Belle's presence can change him. Placing Belle in the role of his savior, as the person who guides his good or bad behavior, puts her in a position of responsibility for a man who she should be running away from as quickly as she can. Upping the level of his cruelty to show the extent of her goodness only makes this worse.
The writers actually did some clever things with dialogue in this episode, and it was intriguing that "showing her the man she fell in love with" did not involve Gold showing her how good he can be, but showing her how dangerous he can be. That, at least, was an accurate and self-aware take on Beauty and the Beast. We saw last season that the fairy tale characters lost all of their defining good qualities in their Storybrooke personas, and so Lacey doesn't like evil!Gold because she sees the good in him and wants to bring it out, but because she revels in that darkness... yet the setup of their story in Fairy Tale Land went from interesting to disturbing, especially if we're supposed to see them as one of the "true loves" of the series. Belle loving a Rumplestiltskin who is only ever neutral-to-good to her, who she believes can show that goodness to others... that's one thing. Belle loving a character who shows that he is cruel and evil, even to her, on the assumption that he can be good, and that she can bring that good out him... that's another matter altogether.