Why do some U.S. military personnel berate other branches of the military without knowing the facts?

OK first off, the guy really has no clue what he's talking about. That said there is a HUGE rivalry between branches of the Armed Forces. The Marines are the Presidents own. (Uncle Sam's Mindless Children) and all the other branches are jealous. The Army gets the best bullet launchers (I was Army and got a lot of grief from my Marine Uncle) Air Force (farce) (wing wipers) are the fast strike of the military and the Navy (squids/ mop heads, etc) are the sea farers. We all hate each other when esprit de corpse comes into play but we all have each others backs when the defecation slams the rotary oscillator. I hated SEALS when I was at Benning but I was glad to support em when I was in Iraq. And I hated the Jar heads training me to be a sniper but I was glad they helped out in the Desert as well.