'The Sinner' season 2 episode 7 leaves us wondering if Julian actually deserves our sympathy

After episode 6, we had predicted that Marin (Hannah Gross) might be the hooded-figure. Turns out, she actually is. In fact, it was Marin who had left behind clues through which the two detectives were able to unravel the secrets about Julian (Elisha Henig) and Vera Walker (Carrie Coon). However, as always, fate had something else in store for the girl who spends most part of her life wandering and trying to fill up the gaps in her life.
Episode 6 confirmed that Marin is Julian's biological mother but the question still remains why did she leave? Although episode 7 answers the question vaguely, and we can only hope that by the last episode we will get to know the actual reason behind Marin's disappearance, it puts forward a different side of Marin. She was always projected as a character who was lost with no ground beneath her feet, and who could not take care of the baby whom she had given birth to. But in the last episode, Marin returns as an evolved person who has been clean for three years.