To this day, more than 73,000 troops remain missing from World War II alone. Unlike Maupin, most of them will never be found. But the search, though it may be in vain, will never end. The oath to never leave a fallen comrade is a promise made to each other, that even if we die, our brothers in arms will do everything they can to bring us home. It’s a mission that hasn’t ended, and as long as wars continue, it never will.
I think it portrays a human aspect of Riker. He's usually professional and very passionate about his duty to a point you'd think he's a high officer of Nazis or some kind of fascist regime.
In the aspect where he is deemed insubordinate to Jellico, it is in regards to show the portrayal that he LIKES being First officer to Captain Picard. Think about it. It wasn't just the ship Enterprise that made Riker refuse command of his own ship. It was the environment around him. The people in this crew became his family. So he treats them like family. His professionalism began to wear thin as his feelings towards his peers went beyond that of just his own job.
So in Jellico's eyes, yes he was insubordinate. I don't think it makes Riker a universally insubordinate. I just think that happens often because Riker is used to the way Picard does things; rationally and diplomatically. Jellico's method involved trickery, cornering tactics, and aggression that would provoke and instigate. Yes he was an expert in dealing with Cardassians (I believe it was them) in that he knew their general behavior but as Troi said (whom I think is the most useless character despite having such an amazing ability) he wasn't sure of himself about anything he was doing.
To Riker, who is used to Picard's firm/confident yet rational and diplomatic stance where he doesn't get cornered but doesn't use aggression and can corner other people through reasoning, doesn't accept Jellico. It's not right. The way Jellico handles his business and ordeals is wrong. Even his demands he asks of his crew whom Riker began to see as friends and families seem a bit too strict, harsh despite the captain not taking time to get to know his own crew.
Jellico's observations were not wrong though. All of the crew WERE obedient and did their job as he demanded but Riker clashed with the captain. This is his job. First officer as well as First Sarge's job in a company or a ship like this is usually 1st catering to your commanding officer's needs/safety then establishing that the rest of the crew is being treated right. Riker is the bridge and buffer between the crew and the captain. If there is an issue the crew feels, it is Riker who must bring these issues up to the captain. He is the next commanding officer.
As for his treatment of Shelby, she is kind of a b**** but realistically she's doing nothing Riker hasn't done. Riker was just as arrogant when he started out in season 1.
This just portrays a human side to Riker who is seemingly perfect at everything he does. IIRC someone also told Data he is more human than any person there at the time (which were mostly senior officers) implying the senior officers demeanor was professional rather than humane.