I think this best sums up our distaste for Starlight and her reformation

She commits abominable and needlessly cruel acts (She was a cult leader and kidnapper who stole ponies' Cutie Marks and used frighteningly real brainwashing and even borderline torture tactics on her victims and later nearly doomed Equestria in revenge for the destruction of said cult, yet in the Season 5 finale she gets more Easily Forgiven than even the other redeemed villains in the series, while her Freudian Excuse of losing a single childhood friend when he moved away (who she seemingly never tried to stay in touch with) after getting his cutie mark came off as a very feeble Start of Darkness since Apple Bloom and Moondancer went through similar situations without falling to villainy. Season 6 tried to fix this with Starlight expressing disbelief over how forgiven she was, but she nevertheless continued to receive constant lenience and forgiveness despite repeatedly making the same mistakes. Not helping is the fact that moments that were supposed to show how much Starlight progressed came off instead as others holding the Jerkass or Idiot Balls to make her look better. Season 8 revealed Starlight had an otherwise idealistic childhood and a doting father with her "dark past" treated as a one-off gag; to many viewers, this made her Freudian Excuse come off as totally pathetic and her breakdown over it at the end of Season 5 seem like nothing more than a whiny temper tantrum.

7582939
That is a perfect summary of why we hate Starlight.

That and she's something of a Creator's Pet.

7582939 Dude, you NAILED it, and I couldn't have said it any better myself.

7582948 Exactly, on both counts.

7582939
Well done,

7582948
What would be your response to those who try to downplay the things she's done by saying she didn't intend to destroy the world, and that in the preceding seasons, she had good intentions?

7583093
Depends if they ever use the phrase "Starlight Glimmer did nothing wrong".

7583114
Some even use the fact that since she didn't stop the Sonic Rainboom, technically what she did never happened. They say those timelines never came to be. They blame Sombra, and Chrysalis for taking over Equestria, but they deny the fact that she caused those events.

If she never tried to mess with history, those events never would have happened, so she is responsible for those events indirectly.