i saw a few posts explaining how the staring sound persists if it plays while you try muting the sound, but that was reported in 1.4.6, well before the new sounds menu in the 1.7 snapshots. my issue is a bit different though:
how to reproduce:
1.turn the enemy mobs sound slider to 0%
2. stare at an enderman
3. notice how the sound effect for staring plays, but not any of their other sounds like teleporting, damage, passive and agressive noises (which is what should happen).