Oh dear. Has bobcat Goldthwaite gone too far with his movie God Bless America?

[Bluenorthwest]

25. I'd say that anyone seeing this as 'wish fulfilment' is part of the culture getting satirized

The DC snipers were an adult with issues who got a teenager to join his spree. It is not a necessary element of satire that the target of the satire is an exaggeration of a 'supported idea'. Any fact of reality is open to satire. It is that simple.
Of course, none of us here can critique the film with any honesty as we have not seen it. So any discussion of the content of the film much less of the larger message of the film, if that message is successful, if we agree with the premise, all of these aspects are unknown. You do not know that this film says '"there's a prat - let's kill him - yay! He's dead!" and while I also don't know that it does not, the work of the filmmaker would suggest that such joy in death is the opposite of what he does. To assume that the message is as you frame it, as you write it, as you create it is an assumption which comes from you, not from the filmmaker.
Nothing is "unacceptable for comedy" that is part of life. Nothing. This is a world where Dexter is a huge hit show. He kills people. It is amusing. It is meaningful. It is humorous. The theory that "unacceptable for comedy" exists is unsupported in the history of theater, film, and comedy itself. The only thing "unacceptable for comedy" is not getting laughs.
Comedies are often centered on people who are not supposed to function as heroic. Note that many, many comedies exist that in which all the characters are criminals, Mafia, hitmen, you name it. The list is endless. Endless. Characters of no decency are great comic fodder. That's why there are hundreds of such films. Hundreds.
Also the notion that 'tragedy' is high art which can address things mere comedy can not is a mistake. Dying is easy, comedy is hard. Comedy makes it easy to discuss issues that otherwise are taken as far too serious. Tragedy is far more limited in that regard. Not that there are 'off limits' areas for tragedy, just that the melodrama often takes the tragedy to maudlin places when it is 'too serious' or 'too like life'. A comedy fails if it is not funny. So it is really easy to find out if audiences as a whole find it funny. Show them the film, if they laugh, it worked. If they don't laugh, then it is not comedy at all, and most people will set the whole thing aside.
The idea of claiming a film is glorifying that which it mocks might hold merit if one has seen the film and has reasons to think that which they can communicate. To say '"unacceptable' sight unseen is without merit. Got to see that which you condemn or that which you praise.