It's Simple

Kinky.

Nary a one. Was in the mountains near Las Vegas, Nevada. Not a lot of flying bugs here.

I have done nekkid in public on a number of occasions. Kayaking, beaches and horseback riding. All great memories.

Flexibility would be a different issue. Tai Chi in public uses loose clothes, but nothing wrong with nekkid Tai Chi either. I tend towards nudity because it feels good and free.

Actually, tight spandex, by restricting movement, forces you to work harder to make a muscle movement.

You're 100% right on deriving greater benefit from freedom of movement and less body heat retention by exercising naked but I don't possess your guts to do that regularly. I guess when you get down to it, the important thing is to keep exercise a priority, whatever your choice of dress--or undress. You did forget to mention that exercising sans clothing does cut back on the amount of laundry that needs to be done!