I understand what Pudding did to Sanji was horrible and I can understand diehard fans would resent her but the Pudding who did that and the current one are not the same imo
You don't change your personality over night.
She didn't leave Big Mom after that -- but Sanji left Judge.
She's still relying on Big Mom while imprisoned. - Sanji doesn't willingly rely on Judge.
She has not shown massive change. Just infatuation that made her 'see the light,' and save the only person to show her kindness.
Pudding isn't in love. She's infatuated with the first person to be nice. She's a silly little girl who has severe mental instability trying to get with the first nice guy after emotionally abusing him and manipulating him out of his first kiss.
That is not a healthy relationship.
Then she had the one fruit that makes her an unreliable narrator should they ever argue.
Unless she shows massive change, she is not fit to be with him.