Does not matter there is no defense for QS to be in the game that the majority of players will ever accept. It is not wanted or liked other then by those that defend it or do it.
There is no reason for it to be allowed it is not needed. For using the logic that it should be allowed just because some can do it would mean that those with a sg should be allowed to get full map kills because they can aim well with it. Until that happens those that do not like it will never accept it no matter what defense or should I say excuse it used by QSr and those that defend it.
It is only in the game to keep those players as sales and revenue not because it is fair or balanced or really needed by the game or the rest of the players.
It could be completely removed and not hinder the use of snipers by those that use them in the traditional manner at all. Therefore it is not needed by anyone but the QS/TS/Feeder/Montage maker.