I grew up on military posts around the world. At the theater you stood for the intro star spangled banner short before every feature. You stopped and faced the flag at the end of day ceremony at some posts even if you were only a dependent. The first time I was in a civilian theater when I was 13, it was a culture shock when the previews started and then went into the main feature. I grew up on posts until I was 13 while the only US posting I was at, 2nd-3rd grade years, and my father didn't allow us off the post without being with us due to working cold war USAF Security Services. He worked for SAC as a Russian transmission translator.
I watched from 13 until now a very slow relaxing in social standards for public respect of the president, military, and the flag. Some of that was learned by children because you learned respect of country at home, public school, and when you are out in the public learning to fit in. And some people used to fake the respect or else, because the social majority practiced it and didn't tolerate disrespect of it. Today the social majority don't and we have fewer who reflexively respect the position of the president and those associated to that position.
Pragmatically holding your applause as an adult is one thing and a choice of conscience. In public school and even what passed for public school on military posts in the past, you were told it was the proper polite thing to applaud public figures who represented our government especially the first lady. I will venture that was at a time the public majority practiced respect of the president, military and flag.
I've had the opportunity to watch times change where respect for social institutions has gone from being expected as part of your civic duty, to something that can get you fired or taken to court if it is the wrong social institution.