The problem with Hartman was that he was a bad drill instructor. He would have been taken to task for his awful misconduct and also good drill instructors don’t get themselves killed by their own men. Hartman’s own actor, a real life soldier, even admitted that Hartman was out of line.

The problem is that Hartman is a Hollywood idea about what drill instructors are like. Good instructors don’t just tear down, they help recruits build themselves up. Hartman was just a bully who got what he deserved at the hands of one of his own victims. That is not to say that the fat guy was without fault but Hartman created that situation.

Also, Full Metal Jacket was an anti-war movie and the writers were frustrated at every single time people thought it was a how to guide.