It's hard to get treated badly as a healer in any content, low-end or high-end if you pull your weight and do some decent damage. That is because you are likely already better than almost half the healers out there by just doing that much.
However you might from time-to-time find some oddball saying healer should only heal and stuff, because how secluded they are from content that matters. Just never let such comments get into your head. Shrug it off, don't fall into the pit. This is why I like being mute in pure duty finder content most of the time. I don't have to broil over non-sense by people whom the hardest content they will ever do in the game is expert roulette.
In savage content, as long as you come prepared and even explain "hey we need a cooldown for that critical hit". Just being honest what the hardship they are causing, it's hard to argue, people should adjust when they are pugging.
