Of the times I've run into these healers, they are always just terrible players, plain and simple. They will usually fall on the convenient excuse of "it ruins the immersion".

Every class has a wide set of tools available to them. Some abilities may only have a very niche use, but can still be awesome at that time, and there are few abilities that are almost exclusively for PvP. But a healer just instantly dismissing half of the tools available to them is just a bad player