"Try having an operation with marines, army, navy and airforce trying to operate together in this example!"
Marines flying Navy minesweeper MH-53s (without intake dust-filters), refueling from Air Force C-130s (whose encrypted radios wouldn't link with the USN helos' differently encrypted radios), with Army troops aboard!
Just because it was decided that all 4 services had to get their share of "glory", so no one would feel left out.
Of course, it would have been unthinkable to use Marines to fly USMC CH-53s, refuel from USMC KC-130s, with Force Recon on board, absolutely impossible!