"Looks like some midshipmen need their butts kicked."
I was not a midshipman, for openers.
But when I was in training in the military, we WERE given breaks. Our training leaders were in charge. We did as we were told.
So I think your concern is misdirected.
If you think this is a big deal, be upset with academy leadership, for not having the midshipmen sit continuously at attention for an indefinite amount of time.
There seems to be no harm done by a photo showing busy young people getting a breather.
Those Mids were making the best use of their time at the moment. I am sure leadership recognized that. When it was time to listen and respond, they did that well too.