Yeah, it's one of those movies.
The thing is, Skeletor gets stranded with the kids somewhere on the way to Horde Prime's lair, and he not only ends up bonding with them, but also falling into the Christmas spirit himself and ultimately helping He-Man and She-Ra save the day. I should have been impressed by this unexpected character arc, especially since the characters in He-Man are usually flatter than the paper they're drawn on, but all I could do the whole rest of the movie was cringe and groan, "No! Don't puss-ify Skeletor!" at the screen. But why? I never watched He-Man or She-Ra as a kid, so it's not like I have any nostalgic attachment to Skeletor, and I've always loved villain redemption stories. Why on Earth (or Eternia) would I hate seeing the skull-faced lord of evil save someone?
I think a lot of Skeletor's charm comes from how over-the-top evil he is and just how much he relishes being evil. You love to hate the guy. Also, it's hard to take him seriously as a villain in the first place when he's so easily defeated all the time and he talks like Inspector Gadget on helium, so I guess he needs to be so un-apologetically evil to make up for it. In any case, I'm glad that he's actually very reluctant to do good in He-Man and She-Ra: A Christmas Special and that he clearly has no intention of staying good after the movie's resolution.
Now that my mind has been opened to unabashed baddies, I have to wonder: is it okay for a villain to just be evil?
Saturday morning kids' cartoons are one thing, but what about movies, shows, and books that are meant for more mature audiences? A pure-evil villain is certainly functional; Sauron and all of his minions from Lord of the Rings didn't have much motivation beyond just being evil, and not many people seemed to mind that. In more recent years though, readers and audiences have come to expect a little more from villains. We want bad guys with depth and interesting reasons for what they do, along with maybe even some pathos that helps you to connect with them. Just chalking a villain's actions up to "because he's evil" is generally viewed as lazy writing nowadays.
For instance, take the villain Malekith from the movie Thor: The Dark World. We know that he's a dark elf who's race was nearly wiped out in a war with Asgard centuries ago and that he wants to fill the universe with darkness so his people can start a new life, but we don't know who he is as a person, what his personal backstory is, or even what a dark elf is. I suspect that a lot of scenes explaining those things were cut for time, but the scenes that we do get present Malekith mainly as a member of an evil race who wants to get revenge and take over the world. It's nearly impossible to relate to him or feel for him, which makes it very difficult to get invested in his plan. As a result, his character has been almost universally panned by critics and viewers for being unmemorable and underwhelming. It also doesn't help that he shares the movie with an engaging and complex villain like Loki.
It's the same case with slasher villains like Leatherface and Michael Meyers. What makes them work as horror movie villains is that we see no humanity in them, to the point that we never even see their real faces. When we can't associate anything human with them, our senses of fear convince us that they are something super-human. In fact, a lot of filmgoers have complained that the remakes of The Texas Chainsaw Massacre and Halloween ruined the Leatherface and Michael Meyers characters by delving into their backstories and showing that they used to be normal people. They were "puss-ified," if you will.
I guess I just answered my question about whether or not it's okay for a villain to just be evil; it is, but not for every villain. But what's the deciding factor? Why does being evil work for some of these bad guys and not for others?
The answer to that, at least from what I've gathered, is that purely evil villains are not simply characters. They're also symbols. Sauron and his One Ring symbolize greed and corruption, the Joker symbolizes anarchy and chaos, and slashers symbolize fear of the unknown and the irrationality of that fear. The focus of the story is not so much on what they do, but on how it affects the characters they do it to. I'm actually wondering now if Michael Meyers would stop "resurrecting" if people in the Halloween movies stopped being afraid of him.
A villain like Malekith doesn't work strictly as an evil-doer because he doesn't stand for anything particularly bad. Okay, he wants revenge on Asgard for winning that war that almost wiped out his race, but that stops being a personal thing for him halfway through the film. You can't even really say that his goal of destroying the universe to create a home for his people demonstrates how good intentions can be corrupted into a force of evil, because we have no idea whether or not he was actually corrupted. He doesn't have enough personality or screentime to properly convey whether he was good or evil at the beginning of the story. I sincerely think that Malekith was meant to be a complex and sympathetic villain, but his development scenes were stripped away and he didn't have the right subtext to work as a purely evil villain either.
Bottom line, a villain who's only motivation is to be villainous has to represent more than just the character he appears as. It is lazy writing to make him evil for no sound reason in this day and age, so the writer creating him has to harness a different type of creativity to keep that villain engaging.
But sometimes, if the story is just being told to make us laugh, it's enough to make him love his job.