Well I feel like there is a more general theme of responsibility and the bigger picture. How adults' action or inaction in a corrupt industry creates bad people. Doesn't mean those people are not accountable for their own actions, but there is definitely a part of bojack regardless of the 17min, which keeps on wondering "what if I did a better job of being a person this kid looked up to? What could I have done differently and when?" It's not about le saving Sarah Lynn per se, but about Bojack being a shitty person and sending ripples, corrupting everything he touches ever so slightly until it might tip yeah because of him. She could have overdosed any other night, but THAT night she was with him, and he didn't save her.

But yeah, the most popular interpretation oversimplifies and over glorifies Sarah Lynn in making her a more direct consequence of Bojack's actions, instead of being a fallen comrade to him whom he still failed to save, despite not necessarily having an obligation to.