It’s a respected uniform in our day and age…
For example in the 1800 only the rich would wear hats the higher the hat the richer. We are the children of hashem we come from royalty, it’s only right to dress the part,no?
A white shirt is either a higher class business man, a partying guy, or a frum Jew, you are able to tell this from afar… We are the am segula would you want any different??? Ok you can say it’s alittle odd to wear it on certain occasions but on a regular day you’ve got the Kippa, you might as well dress it up and make a kiddush hashem and wear a white shirt. It looks more respectful and the goyim dont look down upon it they look up to it… So why in the world would you adorn a t-shirt or any other colored shirt??? If you do you are missing out on so much!!!