From an outsiders' perspective, the monster would obviously seem to be far more monstrous than Victor, in Frankenstein. However, and obviously it depends on the reader's own perception, the monster is a victim of his circumstances, at the mercy of Victor in all that he does.
Victor has no excuse for reacting the way he does and his failure to take responsibility for his actions is what drives the plot of the story. He accepts accountability only minimally, agreeing to make a mate for his creature as compensation and to provide "a small portion of happiness." He reneges on this promise, too terrified to contemplate the situation with two creatures and potentially more.
Instead of the proud moment when the monster comes alive, Victor having dedicated two painstaking years of his life to his creation, is horrified and disgusted. Victor never realizes that it is his behavior towards the monster and his rejection of him that turn the monster to vengeance; Victor believing that it is the monster's own doing.
Although he comes from a loving family, Victor is unable to see what the monster craves and his selfishness and self-absorption is relevant to the end when he will die as lonely and rejected as his monster.
In my opinion then, Victor, who has the capacity for love, could have changed everything whereas the monster has no control over, nor capacity to understand, the feelings and sensitivities of others. How could the monster learn compassion when he has not been shown any?