This is particularly glaring considering that, of all the horrible people in this story, she was the one who saw the damage she had caused and did what nobody else has done:

STOP. Quit. Leave.

And, while she snitched on Jimmy,she also snitched on herself.

She didn't go to the police, or DEA, she went to Howard's widow.

She wasn't under pressure. This wasn't Skyler, caught in the cross hairs.
She was free & clear.

At worst, you could stretch and say that the call from Gene rattled her, made her fear that she was going to get caught, and decided to get ahead of it. That's a pretty big maybe though, considering that the most reasonable conclusion here is much simpler, and much more in line with what we've seen from her character:

She had a crisis of conscience. Unlike everyone else, she didn't make a beeline toward the darkside. It was a slow, gradual change- and, again, she was the one saw the damage she had done and realized she didn't want to continue.

Despite this... you still see her as the worst of the worst, and the one deserving of getting murdered.

All while moralizing about how awful she is for snitching on Jimmy- despite the fact that Jimmy was the devil on her shoulder this entire time, while she was always the angel on his.

You talk about Mike and Jesse being these guys with great hearts, despite Mike being a cold blooded murderer, with countless bodies on his hands, not to mention serving as the primary muscle for one of biggest meth dealers ever, making him intimately complicit in countless crimes. Same with Jesse for cooking that shit.

Kim's crimes are exponentially less and smaller by comparison- and her redeeming qualities are arguably greater.

So it's... interesting, that you're so over the top in your hatred of Kim, let alone your desire to see her shot in the head.