To be honest, I don't really remember what the quote went with. I'm pretty sure it was a few pages back (I'll edit this after I check it). I may have read things wrongs, but from what I understand, you tried to tell the healer that they were healing in cleric and they said something along the lines of, "It's okay, just keep going, don't worry." And you responded with something like, "Okay, but it's not really how you're supposed to heal." Then after a bit you had kind of the same exchange and then the healer got defensive. Then you proceeded to contact them outside the dungeon. The issue I found with this was that you tried to contact them outside of a dungeon. Yes, you're being quite helpful, and if I was in that person's shoes I'd gladly thank you can carry on my merry way. But, this person may have been told that multiple times and have gotten tired of it. Yes, it's kind of dumb for them to continue on with their way of healing when they've been told otherwise, but there's really nothing you can do.
The mentioning in the dungeon was alright, I think that was really great and shows that you care. But if you did indeed try to find them after the dungeon to tell them they are wrong, that's not really right. There's no other way I can explain this. They've shown that they obviously didn't care, and you're probably not going to see them again anytime soon in DF anyways. You really can't fix stupid sometimes :/
Like I said, I may have my stories messed up and I'm honestly really sorry if I do. I'll delete the post if that's the case, but I'm just kind of sad that people actually go to this extreme because they feel like it's helping the person.
P.S. I take back what I said about forcing and idea on someone. I now see it as suggestion as you were trying to be nice and helpful about it.