The gold missing link is a 9spd link. Not a 10 spd one - thus accounting for the difference in width.
Negative. That is a 10-speed KMC link, right out of the blister pack. It also happens to be precisely the same width as the one that came with my KMC X10-series chain. I have 9-speed KMC master links as well, considerably wider. I also have a Dura-Ace 7900 master link here, and it's closer to the width of the KMC than to the SRAM.
The huge side clearance
is precisely the point of the photo. We all agree: (1) got to be careful to use an appropriate master link, and (2) that one's definitely
not 
For me, I'll stick with the PowerLock on the SRAM 10
xx chains.