I'm not a proponent of war of any kind, and I live in the Washington, DC area also.
I have seen the show several times (21 Princess cruises to date) and it is trying to take us back to another time, the 60's period? I believe that the scenes are important to the point of the song. This is not a new show or part of the show by any means.
As for the response from Princess, just what did you think someone on board the ship was going to do? And the attitude at which it is presented is important too.
I would imagine that there are people on that cruise who saw nothing wrong with the pictures and that they felt they made the 'point'.
If you were offended by them, then you should have simply gotten up and left.