How many people actually go round 1 shot killing from the hip ?
None. Since none of the sniper rifles can actually one shot kill to anything but the head. And the chances of you hip firing a shot to the head with the sniper rifle are so remote, i can guarantee you've possibly only seen it once, and now use it as an example to demonstrate why snipers are wrong.
Have you actually played as a sniper before ?
If so you'd know that the unzoom and re-zoom required on bolt action snipers, and the bullet drop on all but the top sniper rifle, make for very realistic sniping. Aiming standing up without any kind of support is hampered, and only a headshot will 1 shot kill.
The game rewards sniping the way it was intended - prone, up on a hill with a bipod, holding your breath and whilst spotting your enemies for your team.
Granted you can slap on Holographic or red dot scope, and go sniping at close range with it, But you still have to aim for the head