You need to look at it mathematically, cutting your own dps by 20% for ballad so the healer could dps a bit would not help anyone out at all, healers need to heal or people die, and by cutting your dps you are making mobs take longer to kill which is making the healer have to heal more.

The faster the mobs die, the faster the tank doesn't take damage, ballad is used if the healer has no mana for some reason and even then they have saints shroud/potions.

The person that was bothering you about it was actually correct and you were in the wrong by gimping the partys potential dps.