Oh yeah the movie was hilarious, but the guy who was critical of the program in real life was an idiot.

It's real in that the actual facts of it occured, but the authors interpretations of events were almost all incorrect.
View it through the lens of a person who didn't actually know how development works.

The main guy wanted to do big live fire tests. The testing range wanted to skip them because they already knew that the vehicle would fail, or because they didn't yield workable data.
They wanted to do smaller, more statistics oriented tests, so they could better direct development.

Basically he wanted to fire Russian antitank rounds at a fully loaded vehicle, when everyone knew the result would be "it blows up".
He called it honesty, they called it needless waste because it didn't produce data they could actually use.

The results of the congressional inquiry was, rather than being "add more armor", that his transfer was because of a disagreement on methodology and an inability of his office to work with the testing laboratory, and that the army had resolved concerns that he raised.

Lot's of details were misrepresented. Things like filling the gas tanks with water and loading ammo with sand during live fire tests may seem like cheating. But penetration into the magazine or fuel tank can tell you the vehicle is vulnerable to secondary explosions without those explosions turning the vehicle into confetti.

To the average Joe, any military development project is going to look like a boondoggle. They don't know about procurement bureaucracies, economies of scale, or the expense of product development. The Ford company spent more to develop the Taurus than the US spent to develop the B2.

I'm also going to put on my tinfoil hat for a second and say that lots of myths about American Military incompetence are encouraged. It's a good thing that our enemies think that our equipment is dogshit and our Generals are corrupt.

What other's have said, but here's Lazerpig pulling apart the controversy.