Which icon?
The "ongoing sync" icon is blue on purpose -- so it's not mistaken for the "new messages" icon.
Yes, I know that since 4.0, status bar icons are supposed to be pure white (and the system darkens them automatically), but hey:
1) there are plenty of apps with color icons still and
2) Android system colors are like skirt fashions... things always change and it's always "now even more incredible than ever before"...
( Personally I'm very disappointed with the grey accents in stock 4.4.... just not enough contrast... I guess it's called "minimalist design"... why didn't they go for The Black Square by Malevich? )