I feel that a lot of Frankenstein (book) fans fall into a trap of assuming black-and-white morality: Victor is bad; the Creature is good (presumably in response to the wider belief that it is the other way round, due to adaptations painting the Creature as unintelligent and a monster). However, it is my opinion that this is a flawed reading, lacking in nuance.
Yes, Victor has done bad things, and his reactions to the Creature are often unfair. (I don't think many people would necessarily do better, but that's for a different post.) However, the unjustified moments are mainly towards the start of the book; as time goes on, and particularly after he believes the Creature to have killed members of his family – innocent people – it becomes clear that, even though the Creature was not malevolent before, he is actively a danger now. Would you forgive the person who killed your family?
It also seems relevant to note that Victor feels guilt for the Creature's actions, whereas the Creature doesn't feel guilt even for his own actions. This seems commonly brushed over on the internet at large – Victor is not ignoring the consequences of his actions. The whole book is his confession of his guilt, and while it's clear that he's biased against the Creature, it does not seem that he is trying to downplay his own wrongdoings.
And that brings me nicely on to the Creature himself. He starts his portion of the story as an innocent character, if not a child as such, childlike in his wonder and his view of the world. It's fair to assume that a lot of people's sympathetic readings of him take a lot from this portion of the story. Shelley shows that he only becomes cruel after being horribly mistreated: by society, by people he viewed as potential friends and allies, and arguably by his own creator. However, to downplay his later actions is unfair both to the messages Shelley wished to convey, and to any reading of him, Victor, or the characters he killed.
The Creature killed multiple innocent people, including a literal child. He was aware of the hurt he caused (as evidenced by his threats towards Victor), and he reveled in it. It is perfectly acceptable to like a character who does bad things! But it's also important not to brush aside the things they do for the sake of making your favourite character look better. (I have certainly been guilty of this in the past.) It leads to weak readings and misinterpretation.
To be clear – I know this post is, overall, favourable to Victor and focuses on the Creature's wrongs. My actual reading of them is considerably more nuanced, with neither of them being a 'monster' or a particularly good person, and I would be happy to discuss that reading further. However, Tumblr users at large seem to read Victor as 100% evil and the Creature as 100% justified (particularly in the wake of the recent Frankenstein film), and in a post attempting to inject some more nuance into such a black-and-white conversation, I thought it would be best to focus on what is ignored.
If you've read this far – thank you. And although I doubt I'll change many minds, I hope people will at least consider my words here. You are free to come to your own conclusions, and I'd love to hear your thoughts!