Let me try coming at this from a different perspective than what you might be looking for. Rather than providing critique in reference to this specific show, I will attempt to persuade you by examining the way it appears you're viewing art itself.
I would argue that art in and of itself is devoid of meaning; that is to say that it lacks any meaning that isn't put upon it by the viewer themselves. You may have heard the term "Death of the Artist" before (I'll abbreviate this to DotA for the sake of brevity), which is essentially going to form the central point behind my disagreement with your disapproval of this show.
If you don't know, DotA is the philosophical perspective that says art is detached from its creator, as art is meant to be consumed by an independent party. I think you are unfairly targeting a Netflix show here by that reasoning, as the show itself does not provide "glorification" of suicide any more than Manet's painting "Le Suicidé" does.
The depection of something within art doesn't immediately make it a glorified version of the event depicted. Take for example a violent movie like Tarantino's recent film, "Once Upon a Time in Hollywood". This movie contains violence, yet it doesn't glorify or endorse it. The violence depicted just is. The only value statement that could be applied would be that decided by the individual who is viewing the film.
Likewise, the song "À Tout le Monde" by Megadeth, can mean anything that the listener decides. The person who wrote this song, Dave Mustaine, said in an interview that its seemingly pro-suicide lyrics was not at all what he intended to convey. I would argue that it doesn't matter what he wanted to convey, all that matters is how the individual interprets it. To you, this song may glorify suicide, while to Mr. Mustaine it may not. Neither of your opinions are more valid than the other.
Thus, to tie this back to the show in question, I would suggest that you ought to reframe your perspective on art as a whole. "13 Reasons Why" only glorifies suicide because you decided it does to you. To imply that it inherently glorifies suicide is absurd in my view, as we would not suggest that a war movie, such as "Saving Private Ryan", undoubtedly glorifies violence. The violence and suicide are depicted, yes; but the value statement "glorified" is up to the individual and can't be an inherent property of the art itself.
TL;DR DotA