I said this in my last post - at the beginning of a massive pull, it MIGHT be kind of hard to DPS while keeping the tank alive, but after a few mobs have died, there should be no issues.
With regard to most boss fights - if you aren't DPSing during those, what the heck are you doing?
People aren't making these "stories" of healer down time up. If you don't have down time, it's because you aren't playing to the job's full potential, and if you don't try to improve or at least entertain opposing viewpoints, you are being childish and lazy.