Saying things are comparable shouldn't the same as saying they are identical. In should mean recognising that they are different, but that the differences and similarities deserve attention - comparing them, in fact.

I agree that the industrialised killing machinery built out by the Nazis should not be used as a standard against which other horrors are measured. It risks suggesting that this was less unspeakable than it was, which should never be done. But it also has the danger that weighing these acts in the same scale, it tends to makes other acts of inhumanity seem relatively minor, and that should never be done either.

The Shoah and the Nabka were very different indeed. But both words mean the same, respectively in Hebrew and Arabic - catastrophe.