I know most officers aren't like that,
Officers don't train troops in boot camp, and despite being around them constantly for the last 20 plus years, I've never heard one scream. Being college educated (and officers), they tend to be calm and decidedly non-testosterone-filled cretin's. Self important, sure, but that's hardly unique. Yes, the people doing the training tend to yell a bit, (though screaming was right out), especially in the first week or so, and are certainly testosterone-filled (even the lady trainers....maybe more so), but it isn't anything like Hollywood would lead you to believe (granted, I did USAF boot camp, but the other branches (save the Marines) aren't what you'd assume either).
Is it? There are, for sure, plenty of meat heads in all the branches...more so in the Marines and Army, obviously, but even there they are in the minority. Believe it or not, modern western militaries don't want or need to be filled with angry, kill happy, men. Having a few around is nice, you kind of need those guys sometimes, but for the most part it is not accurate picture of the people that make up modern, western militaries.