As we all know, the player character is hardly the most intelligent or reliable narrator; to the character, that may have seemed like a sob story, but if you look past the narration and genuinely look at things, you may find a different story.
I think that it was a true story; or at least it was to the Meek leader. Memories are hazy things; hateful memories are even more prone to become blurred over time.
For my part, though, I generally think that was a true story that became blurred over time; the Meek leader lost her sister when she developed her powers; that probably drove some sort of rift between them, and that was when she began to harbor a fear and hatred towards supers; as far as she is concerned, these powers turned her sister into an alien being; her sister was in possession of an incredible power that she would never be able to comprehend or surpass. Even if her sister was very nice to her, did not care that they were different and all, she would never be an equal to her sister.
In my own (imagined) version of events, this began to drive a rift between them; the Meek sister believing that the powers were what drove them apart, the Powered sister believing that it was jealousy and whatever that did so. And these conflicting beliefs over what destroyed their relationship merely aggravated them both. And eventually, the promise of a Powered Community amongst the heroes, and the lack of support from her home, would drive the Powered sister away to live the life of the heroes. Perhaps partially, this was due to a comparison between her life at home and her life as a hero; as a hero, she would be revered, respected, and wealthy. To remain as she was, the Powered sister would have to face what she believed was anti-powered prejudice. So the Powered sister would try to become one of the heroes. And as far as the Meek sister was concerned, this was out of greedy self-desire for power, glory, and money.
As we all know, the attempt to become a hero eventually led to the death of the powered sister, and from the Meek sister’s point of view, everything was ruined because of the powers. It would be nice, after all, to have one single thing to point the blame at and hate, because hatred is easier to endure than grief; and with time and hatred, everything became embellished, facts became twisted without her even realising it, and led the playable character to believe that it was a mere sob story to gain sympathy.
Of course, I could be reading too much between the lines and may have read a bit too much drama-oriented books; but that’s the most interesting backstory I can think of for that sob story, and I like to think there’s an interesting story behind everything.