I don't think too many 2Lts know a whole lot in any branch of service. Yeah, some officers in one branch may be better equipped than others in another branch, but just because all 2Lts are idiots, doesn't give anyone the right or the privelege to shit on them. I saluted officers when I was enlisted because that is just what you do, like it or not. Some officers don't deserve the time of day...do I still salute them? Sure do, but i'm saluting the rank, not the person.
When I finally get commissioned as a 2Lt, you can bet your sweet ass that i'll salute anyone that outranks me, 1Lt and up. They have earned that rank (in my book) so I will give them the respect they deserve. When i'm a 1Lt, (Capt, Maj, etc), will I demand a salute from anyone lower than me? Nope...that's not what it's about. I will let them know in a tactful way that saluting a higher ranking officer is what your supposed to do, but I won't lock anyone up at the POA for it (unless it's blatent).
As far as the Academy grad is concerned, what a tool. That's certainly not how you EARN respect.
Just another Marine/future officer perspective, take it or leave it.