What is the purpose behind the leg shave? It can't possibly be wind resistance which is the most common theory. There are 1000 things you could do to improve aerodynamics/speed before shaving your legs becomes relevant. So what is the real reason? Is it purely 'aesthetics'?
Without knowing the difinitive origin , practical wise it is to aid in the healing of road graze should you come off. Hair is basically dead skin and when in a wound it can promote infection. Trust me, it is excruciating scrubbing bitumin out of road rash. Mind you, I don't know anyone who goes out of their way to fall off.
Cyclists are seen as shaved leg warriors, but so many sportsmen do it. Runners, swimmers (full body shave down), footballers etc all shave for other advantage such as aerodynamics etc.
Then there are the sportspersons that shave down for aesthetic purposes - bodybuilders etc.
I don't think there is any one reason cyclist shave their legs. I even shave my arms before racing. Psychological placebo I guess. I know when I'm shaved down, I'm ready to race. Part of many cyclist/triathlete/swimmer ritual.
Plus my pins look damn good shaved down!
pinkboy