My perspective is if OP doesn't want to do large pulls, then he might want to consider playing a tank instead since more often than not, they determine the pace at which the dungeon will be ran. It really isn't a luxury a healer possesses. What they do possess is the ability to adapt to just about any group and job composition. A player who does not understand this might want to consider playing something other than healer.

That said, we don't know at what point he said this to his group. Was it at the start, or did it happen after the tank pulled everything from here to next week and didn't use any cooldowns to mitigate the incoming damage? If it was at the start and I was playing as a tank or DPS, I would seriously be like, "WTF!?" But I say this often when reading some of the experiences of other players on these forums. I've been pretty lucky and haven't encountered the level of douche-baggery that some of you have.

Either way, outright refusal is poor etiquette, and will never be met with any kind of positivity.