not a personal attack imo
and I commend Don for rebutting the post instead of crying foul.
SDAI's response was an impression that he has gotten from Don's posts and it is a legitimate topic of discussion. We are not solving anything here we are just posting our opinions with the implied willingness to discuss them. When someone posts frequently and passionately on the same subject they invite opinion on their motives and philosophy from those that choose not to ignore them.
A major annoyance to me is the tendency of some liberals to consider any comments disagreeing with them a personal attack. To be fair it would be equally annoying coming from a conservative but it has been my experience that conservatives are not as thin skinned as the more "sensitive" liberals.