I think the fact that Frankenstein's creature is considered more monster than human is more of a reflection on humanity than it is on him. Absolutely, I do not condone his violence, but I do find that I sympathize far more with him than I do Victor. The creature was born gentle, curious, and loving, and he was rejected, abandoned, and even shot when he tried to peacefully interact with humans, all because of his frightening appearance. He looks like a monster, through no fault of his own, and his miserable and lonely life is a testament to our willingness to judge a book by its cover, so to speak. He is judged as a result of his appearance rather than by his character which was, by nature, benevolent.

In large part, the nature of the monster's creation served to condemn him forever to the status of monster despite his having a human "soul" or the ability to feel and think like a human. His enormous size and super-human strength, which give far greater impact to his rage-driven killings, also serve to make him repugnant and anathema to humans so that he is considered a monster rather than a human.

His appearance, having been cobbled together from cadavers, is another reason why he is accorded the status of a monster rather than a human. Even as he comes more and more to feel the emotions and the desires of humans, love, sadness, loneliness, etc., humans cannot look on him with anything other than fear and loathing. This compounds his loneliness and fear, which then drive him to more "monstrous" behaviors, further condemning him.

Why is Frankenstein's creature considered a monster?

Frankenstein's creature is a monster in the strictest sense of the word. A monster, technically speaking, is any animal or plant which is abnormal in its form or structure or which would not or should not occur naturally. Frankenstein's creature certainly fits the bill here. He was not birthed naturally or created by God. Instead, he is a cobbled together mish-mash of various other pieces of corpses, sewn together by Victor Frankenstein and reanimated through dubious means. He is a creature who, by rights, should not exist. As such, he is a monstrous creation.

However, in the modern sense, the word "monster" often carries a connotation of moral judgement. It is often said that a true understanding of Frankenstein requires the reader to grasp that it is actually Victor himself, rather than his creature, who is the monster. The meaning of this suggestion is that it is Victor who has behaved in an immoral way, rather than the creature, who is not really capable of morality.

Victor has created this being because he wants to play God and harness powers that only God should have. He then abandons the being out of fear, failing to take care of it as a father, and so Victor is therefore a "monstrous" sort of parent—he does not behave as a parent naturally should. The creature does, of course, perform acts which are wrong and violent, but the question we must answer is: whose responsibility is it to teach a child what is right and what is wrong? If the answer to this is "the parent," then Frankenstein has certainly failed in his duty towards his monstrous offspring.