A lot of these fanfictions also explore the idea of the reader helping Morbius deal with his inner demons. It might involve the reader being some sort of anchor for him in his struggle against his bloodlust. There can also be themes of redemption, where Morbius tries to be a better 'person' because of the reader's influence.
In many cases, Morbius isn't considered bad. His character is complex and has various motivations and actions that can't be simply labeled as bad. It's more nuanced than that.
In the comics, Morbius is a complex figure. He struggles with his newfound vampiric nature and often finds himself at odds with both heroes and villains. His powers include enhanced strength, speed, and the ability to fly, but his condition also brings moral and ethical dilemmas.
It depends on your preferences. Some fans think Morbius is great in the comics for his unique powers and complex character development. But others might have different opinions.