I don't want to attempt to settle the atheist/believer problem once and for all. I know I can't.
My main point in addressing Mac Donald's "bad things" argument was to show that it is not any kind of slam dunk that should end the argument for anyone.
What IS my main point is that non-believers/secularists/whatever you call them, have been rather insistent that they are being abused or presumed upon by God-talk in the public square. Considering the rather large number of people who do hold such beliefs, I think it actually quite impolite to insist that these people construct some alternative justification just to please the non-theological sensibilities of others. This is particularly true if we agree the issue is not conclusively won by either group.
In addition, Mac Donald's argument is based on a straw man. How often do believers argue "God sayeth" and then leave it at that? They don't. In fact, one of the common critiques of conservative Christians is that they argue too much via a political mindset (like for tax cuts!) and not enough from a prophetic biblical stance!