I don't feel one bit sorry for Summer.
She isn't some delinquent teenager. She was actually quite responsible before she went off on her extended vacation. She even had a good relationship with her mother, father and Jack. Then she comes back as a 25 year old floozy playing the role of a sex kitten hot after her mother's boyfriend.
I really wish when they brought Summer back they would have recast the role and made her a more mature, responsible, intelligent adult.