THCD or Nothing

[Tobus]

Button-down shirts are overly formal.

This seems to have been stated as fact, but I daresay it's just a matter of opinion. Some button-down shirts are dressy, some are extremely casual. I prefer to hike in a button-front shirt rather than any pull-over-the-head shirt because it's more comfortable. It's nice to unbutton the front when I need some ventilation.

A popular choice these days are the short-sleeved "fishing" type shirts with vented plackets, which are made with UV-blocking materials that are supposedly breathable. Or "safari" style shirts in cotton or linen. Both are extremely casual choices to which I would never apply the word "formal". And I do find them far more practical than polo-style shirts or t-shirts.

I suppose my point is that your premise could perhaps use an adjustment with regards to button-front shirts being dressy. They can be, but they don't have to be.