How is that showing off? I think you should ask the crew of the Abraham Lincoln if it is showing off. I would bet they don't think so!
Was throwing the first baseball at the World Series "showing off?" How about cutting brush at the ranch?
The American people like a President who is a leader, who isn't afraid to take the risks. This is a good thing to showcase the Navy, get America's attention, and have some fun.
For myself, I do not want a President who is locked in DC 24/7 and only appears to give policy speeches. That is boring. We are a dynamic country and deserve to have a bit of enjoyment after the last few months.
In addition, he is leaving the ship before it docks, so that the troops get the attention and don't have to be delayed by security.
Quit grumbling. You could be back in the days when Clinton grabbed all the credit for everything, even when he had nothing to do with the success of something. Remember him "taking the hill" in front of the White House? THAT is showing off!