No that doesn't make sense, since you actually need a lot of positivity to push through the bad times. If the despair increases then so does the feelings of hope and determination, remember, all emotions, there is no implication anywhere that her powers to absorb every feeling was altered or in any respect dimmer, and given that she had the mental capacity of an entire collective she should very much have been able to understand why people do choose to go on. I'm not debating that she developed a fatalistic viewpoint, what I am debating is that the concepts that enables people to power through the worst of times seemed so alien and meaningless to her. Like the concept of personal battle and triumph just did not exist. It's just weird and whiny in the end, and hilariously self righteous. They ultimately put an immature kid in a position of power with nothing but a hopped up teen emo perspective, it doesn't make for a compelling villain