To be fair to Sasha, she doesn't speak as if there was a big power imbalance between them or that they are anything other than friends and equals. She says as much in the article. A woman of less integrity, really looking to cash in, would have done a DM Sad Face narrative about being taken advantage of by a prince and discarded. She doesn't do that.
I do agree that his failure to check up on her afterwards reflects badly on him, but teenage boys who've never had to take responsibility for anything can be like this. My ex piped up one day, many years into our relationship, that he'd lost his virginity and got the girl pregnant while still at school, and had no idea what happened to her or whether she went ahead and had the baby. Absolutely shocking, but he was the type to never own a single thing he ever did - he had a similar victim narrative, despite having a privileged upbringing. His parents were horrible though, so that was always his default, victimhood. She was also a couple of years older than him, so he deemed the episode to be her fault. Both my ex and Harry were grown ups with responsibilities when recounting their respective encounters - arrested development, man children both.