I think this is pretty on point, very much agreed.The key difference is that Hal and Wally were created to be superhero protagonists and functioned that was for most of their histories and garnered fans based around that fact before their characters were thrown under the bus for dumb schlock storylines that fans wanted to see undone ASAP. They had to act extremely OOC for those stories to work.
Harley was created the be a villain. The first time we see her she is helping her boyfriend plan to blow up a room full of people. The story that fleshed out her backstory and made her more sympathetic still involved her trying to murder Batman and help the Joker disfigure Gordon. She shot to popularity while in the hands of her original creators and was shaped by them (a rarity with mainstream comic characters) and their final story for her originally ended with her death because it was the most appropriate punishment for assisting in torturing a child into insanity. Dini ended up not wanting to kill her so he wrote her in as an old lady in Beyond time, but that is probably the most convincing redemption she had: she just retired from crime, laid low and didn't bother anyone again and tried to make sure her granddaughters wouldn't go down the same path she did. That is a stronger indicator that she actually changed and wants to leave her old life behind her instead of her bouncing around in everyone's faces and being on the JL when she doesn't convincingly express remorse for what she's done.