Why is Arnold's hair...

boogers n snot

He borrowed Donald's Just for Men.








Looking at the world, through amber colored glasses. 

You get old, your hair color changes.

He wouldn't look right if they dyed his hair back to the youthful dark brown he had when he was younger.

So they compromised with a very pale brown rather than having him be silver/grey.

I used to have a dark chocolate brown hair color 40 to 50 years ago, now mines a pale brown with occasional blondish hairs and my beard gets some white ones.

If you look at his eyebrow color in these photos:
http://www.dailymail.co.uk/tvshowbiz/article-3417497/Arnold-Schwarzenegger-looks-cheerful-girlfriend-Heather-Milligan-land-U-S-soil-Austrian-getaway.html

You can tell he would be almost completely white hair without the dye job and I think his colorist just didn't want to go too dark as to be unbelievable for his age

I know, the color is kind of odd. Seems like with all that money he could find a stylist who could do something better for him.