The acting is fine, there is clear talent in the cast.
The script is the main issue. If you create a world in which even the dark topics are throw away laughs, it's very difficult to then create drama around a subject or scenario where you expect the audience to suddenly care. As a result the attempts at drama or heightened tension in scenes is ineffective. Unfortunately because of this, it's hard to care about anyone or anything in the film. There are a few funny throw away lines which do prompt a chuckle but they rely on such "crass" topics and "taboo" subjects that it just feels desperate.
A long term listener and fan of Ayo Edebiri's podcast (which I would still recommend), a podcast which takes a very righteous angle on roles in films for actors who match the characters attributes (e.g. Jewish actors for Jewish roles, black actors for black roles etc.) I was surprised to see non queer/lesbian actors playing queer/lesbian roles and "Uglifying". On this argument, you could then say why are 25 years olds playing high school students....I personally disagree with the whole argument - an actor is just that an actor - I am pointing out hypocrisy - a word which sums up the film.
Tries to convey a modern, serious "message" within all the comedy but ends up more of a mess.