Walauuuuuuu......... So many version...

The ultimate objective of human wearing cloths is due to coldness....
And slowly evolve to fashion...
And slowly evolve to protection on hazard/war (as said by Joey Christensen)
And now slowly back to nude beach/camp/etc...

If everybody is naked, then erection will be a rare view as we've grown up seeing naked which is normal... and touch here and there would means nothing as it's normal.

The only not normal is when a grown up adult that wears nothing since childhood suddenly walk into crowd that wears something. And vice-versa..