I posted this as a comment on another question but feel it is valid here:
Agreed. I don't always comment on my actions. I handle around 20 - 30 flags a day on SU, I can only imagine how many Marc and Bill handle on SO, and if we had to stop and comment for every single one, we will never have time for anything else. If something is queried we will take the time to respond however.
Diamond moderators have way more to do then the others, and we cannot comment on everything. Reality is every time I have taken the time to respond to something, I have been personally attacked or abused, and honestly, I don't need it. If users can't be mature about using the site, they shouldn't be here in the first place. I don't see why any of us have to open ourselves to abuse.