It’s interesting to see that as the decades go by, the yeshiva high schools still employ the “This is the way we do it, so this is the halachah” system of indoctrination. I’m not surprised , but it is unfortunate. The hat and jacket thing is particularly telling, I’ve been hearing that nonsense for over 50 years.
Let’s wager on what percentage of boys would or would not change their attire if one minute before mincha they were informed that they are about to have a private audience with the Monarch, or a State official, or (gasp) a date with a maidel. They can go “as is” or they can shower and dress appropriately. I wager 99.99% change their clothing.