I think Alex went to Captain Dale Dye's Hollywood boot camp and/or they are listening to the technical advisor on the "SEAL scenes". But then they miss some things like Lt Cmdr McGarrett not shaving when donning the uniform for a cop's funeral or having him serve a three year tour in Afghanistan with the turncoat mercenaryIt seems contradictory on occaions - one episode they interrogate some-one by tyong them to the front of the car the next ep McGarrett's shown ejecting his mag after emptying it. The realistic and the over the top - a strange combination.
Though the not shaving could also had to with the production in terms of when various scenes were firm.