You didn't heard what [Gameclub]Slash Said?
"We Implemented Scar Light For Lower Ranks so that they Could fight Fair With High Ranks, considering higher ranks got accessed to more Guns, XM8 and such.
We are not Planning to change its Rank requirement, It would remain the same as it is"
So yeah, it's intended to Low Ranks, they call you Scar Gay since you're already a Lt. Col. and you still depended on the Scar Light