A dress code inherited from a much colder climate. It took time for our culture to adapt.
BTW, not everythning our forefathers did, was right. Conservative means holding to the GOOD of the past, not simply holding on to the past per se. Otherwise we'd all be Amish.
Alert, Alert. People in line for the procession in DC are not dressed properly. Who cares it is 90 degrees, and they have been in line for hours. They should all be in black wool suits and dresses. / sarcasm.
The bottom line is you really just want to justify a lack of decorum in solemn public occasions. After all, in your world all that matters is your comfort rather than seeking to solemnize something or someone that's more important yourself.
In a veiled attempt to eschew outdated convention and what you might call elitism, you actually hold to a fairly exalted and overblown view of yourself. You feel that we are all equal and no event and no one deserves special attention or respect. When in fact none of us are equal by nature, gift and ability and some do deserve more respect than others.