I wouldn't call rushing a "skill". If you're good at then maybe yes, but few are good at it.
Rushing is as much of a skill as camping.
People have differing perspectives on what consists of skill but the same argument can be used against campers.
A lot of people would say that it is harder to rush then it is to camp.
The rushing playstyle is already handed everything on a pallet. They're given the most extreme perks available and are they can equally benefit from the perks of the more stationary and defense oriented players.
Do you honestly believe this ?
Can you please elaborate ?