Who the Navy SEALS are and what they do is so unique that the flat hierarchy they operate under would only apply to other outliers in human activity. The very fact that they are “elite” speaks of a hierarchy. As a USN sailor I worked with SEALS on marine repair jobs that used their scuba diving capabilities. Unless it is directly related to the job, they don’t even talk to other sailors. The Navy operates under a very rigid hierarchy, and it works very well. The captain of a ship is the closest thing to God on Earth. The US military has always awarded initiative, and every man and woman is trained to assume the next level of command in the event of casualties, but every service member literally outranks or is under the potential command of any other service member across the Armed Forces. In the SEALS, if one Boatswain’s Mate Second Class achieved his rank a single day before another Boatswain’s Mate Second Class, he outranks him and could give him a lawful order if the situation demanded it. They all know where they stand in this scheme, but these special operators are so professional they never have to bring it up. Missions like spying, blowing stuff up, abducting people, or killing them requires a very high degree of trust between the people doing it, since the job is extremely dangerous. If someone makes a mistake doing anything, they’re sent back to the fleet with the rest of the swabbies. It doesn’t work like that in the rest of the world.