This girl (Hannah) continuously put herself in situations that she admitted that she knew were bad for her, but kept doing it anyway. The movie skirted around any actual mental health issues that she had, considering her self-destructive attitude and actions. She made the tapes to blame and shame others for her suicide. While some of the characters were genuinely fucked up, others were just bystanders that she couldn't handle leaving. Alex and Jessica liked each other and dated briefly. Hannah couldn't handle it. Clay was an awkward kid who she pushed away after engaging him physically.
Some of the other kids were assholes, but they're high school kids. Courtney wasn't "out of the closet", and it was a dick move to throw Hannah under the bus, but Hannah could have set the record straight at any point. Justin spread a common rumor that took a kiss to a blowjob, and again, Hannah could have been like "no that didn't happen". Ryan published her poem without her permission. Marcus groped her on a date in a brief sequence that was over pretty much as soon as it started. Zach was hurt for being rejected and lashed out in a truly inconsequential way. Sheri avoided incriminating herself both before and after a fatal car accident. Mr. Porter was trying to help Hannah, but she refused to say she was raped, refused to confess that she has been suffering suicidal ideations, and ultimately refused to be cooperative in any way.
Honestly, the only two people on the list who necessitated taking blame were Tyler, a peeping-tom stalker, and Bryce, a fucking rapist. Both of whom she refused to report to authorities at any chance afforded her.
And after watching Bryce rape her old bestie, she goes to a party at Bryce's house? That was the straw that broke the camel's back, in my opinion. I'm not about victim blaming or anything, but no one was responsible for her death except for her. She didn't deserve to be raped, of course. Even if she went to a known rapist's house and got his in hot top and didn't immediately jump out when he was clearly coming on to her. It's not her fault. But outright refusing to get help, both legally for being raped, and psychologically for being a self-destructive, suicidal person? That's her fault.
The show might have tried to tell a story of people refusing to take responsibility, but it failed. The only person who is responsible for Hannah Baker's suicide is Hannah Baker.