Cermanic irons are still damaging, the difference is that the heating is more even across the ceramic plate... thus you don't have hotspots.
With a traditional iron parts of the plate maybe a little hotter than others, but you may not know it. So.... while you crank up the heat to warm those parts of the iron that aren't as hot, the hotspot is getting hotter also. When you flat-iron the hair touched by the hotspot get hotter and more damage than the hair heated by the other parts of the plate.
From my own experience, I have gotten less damage using ceramic...and my hair doesn't feel as fried and dried after using it...like it did when I was using my other irons. My hair tends to feel silkier and moister. That having been said... I'll admit its probably a combination of the iron and the fact that I don't use that kind of heat often any more. I used to do it once a week, now I go months without it.