I think it's because there is no way people in real life actually do that. Plus there is no animation. Picture yourself dropping shotting in real life. Could you hold your gun steady from standing to the prone position? No. If they put animation into going prone like Battlefield, it wouldn't be a problem.
On a side note, if you drop shotted like 10 guys in one day, I think your chest would start to hurt.
Oh but the knife is realistic? probably most of the people who whine at dropshotting are panic knifers who suck anyway.
Dropshotting only works on noobs.
I never said anything about knifing...
HC HQ all day! Forget the explosives, use a real gun.