No, it's there to force a weapon into its specific niche. The pistol and the DMR are not there to provide you with ultimate supremacy in every fire-fight just because you mastered the motor-memory to rattle off head-shots in quick succession.
The pistol is there to protect you at mid-range from DMRs at spawn. At mid-range, the pistols higher rate of fire (that is, the time between the shot and full reticule bloom recovery) gives it an advantage over the DMR. At like-wise, its accuracy gives it an advantage over the AR. Come in too close, and the time between the shot and reticule bloom recovery is too long to survive AR fire. Get too far away, and the DMR's accuracy at range will overpower the pistol.
Reticule Bloom forces it into its niche.
Likewise for the DMR, only its niche is mid-to-long range.
You are not owed the ability to dominate every weapon in the game, in any situation, with headshots just because you can rattle them off quickly. This is a sandbox full of weapons, all of which should be viable under specific circumstances. If you want to use the DMR and Pistol in close quarters against an AR, you're out of luck.