Personally, I embrace the idea that she is a monster, and one the other characters should overcome in their adventure. Yes, she's vile and despicable, but she is so vile that one couldn't even pretend that she anything but an obstacle to be overcome. This, however, might be overly generous to the authors of the provided scenario. I really have no way of knowing what they intended, or what they're trying to accomplish with this character, or where they intend to take the game. I've talked briefly about this before, but I want to look at a broader question. Just what is the point of Vampire?
First off, it's a game. You sit around with your friends and pretend to be vampires. You might stand around with a whole bunch of people if you're LARPing. The goal is to have fun--get involved in mysteries and action adventures and try to overcome impossible odds. Maybe you focus on grindhouse horror. Maybe you like long trench coats and awesome action and fighting. Maybe you're all about the political maneuvering of various groups. Whatever, so long as your having fun. But, is Vampire really any different from any other RPG?
And this is where it gets thorny. One answer I like is "no." It's a game, you have fun, it's just the tropes and conceits that vary. I'm an old-schooler at heart--I like random tables and random encounters and the like. The "story," such as it is, is the result of what happens at the table. The interaction between Storyteller and Players, between the characters and the world. The story isn't some platonic ideal imposed on the players, but the natural result of their actions and choices.
But the other answer is "yes"--vampire is somewhat different. It's a story of personal horror, a story about the lack of self-control, and coming to terms with the evil that resides in all of us. And this is the defense for Amelina--yes she is a monster. But, Vampire is a game about being monsters. So what, exactly, is the problem?
The problem is that Vampire is not a game about being monsters. It is a game about confronting and overcoming the monster inside us. I want to quote the 1st Edition Core Book here. Sure, the writing is typical early-White Wolf "artistry"--but I think it's important to try to understand what Mark Rein*Hagen and the others were at least aiming for. Even if you don't agree with their goals, or feel that they failed to accomplish what they wanted.
We must learn not to expel the dark side, but to harness it instead. We must somehow come to terms with the Evil, accept and understand it, and then, finally, overcome it...You can not reason with the dark side, it does not understand our world of logic and reason. It must be attacked in a different way. We must become, in order to overcome.
And to me, that's the key. Vampire isn't about playing a horrible monster and glorifying in your evil. It's about confronting the evil that lurks inside all us, and finding someway to overcome it. To face the horror within and emerge a stronger, better person for it. The big bad evil threatening to the destroy the world isn't an ancient thing waiting to rise and consume all. It's part of you, within you, and if you fail to understand and master it, it will master you.
You don't have to play Vampire this way, of course. You can treat it as a tool to tell awesome John Wick style action stories and it works great. Even if you do try to play it this way, you need to vary it up. You need action and romance and broad comedy to make a story work. Hell, even Shakespeare included dumb comedy in Hamlet, and if it's good enough for the Bard, it's damn good enough for us.
But if you do, you have to understand that the more evil and vile the character in question, the sharper the divide needs to be between acceptance and condemnation. If you choose to embrace Vampire in all it's artistic aspirations, you have to understand it is ultimately a moral and spiritual game, and one where actions like eating babies is unambiguously wrong. Any player burdened with such a character should be revolted at that, and spend the game struggling to resist. I doubt such a play would be particularly enjoyable for the player, though. And given the extreme to which they take Amelina, I doubt any player could learn much about their own moral condition through the character.
The theme of "A Monster I Am Lest A Monster I Become" is a powerful one, when used properly. When used improperly, it's teen age "edginess" with no meaning, no power, and can kill everyone's enjoyment.