I've no desire to deprive the grieving of anything that might help: get through this unimaginable horror, and then later on you can deal with whatever problems your coping mechanism has created.
Kushner chooses to believe in an imperfect god, which allows him to maintain his belief while at the same time exonerating his god for all the pain, suffering, and death which befall the most innocent of bystanders. It doesn't work for me. Either this god could prevent all misery, and deliberately chooses not to, in which case I want nothing to do with him because mean. Or, this god who supposedly created this entire universe isn't powerful enough to prevent misery, in which case that first bit must be a lie, huh?
I find it much more comforting to believe that what happens to us is just plain dumb luck (or lack thereof). And that we should all of us feel real sympathy for the pain of others which could easily be our own. And of course, I believe in harm reduction, which means that as social animals we must do everything possible to reduce the misery among us, because clearly no one else can be bothered.