The application of the PE Stamp
My experience is that the application of the PE stamp is the definitive statement, admissible in the public record, that the "stamping" engineer has affirmed the document is compliant with the state-of-the art science and application of engineering standards, codes and best practices and (most importantly) is consistent with protecting the safety, health and welfare of the public. The stamping engineer must decide if he must be involved in the actual internal processes that led to the final document (i.e. being a supervising engineer or not), but I do not see it is a necessity per se. Bottom line, if this inquiring engineer cannot apply his stamp with the aforementioned assurance in his own mind, then he should yield to someone else who can review and stamp. He makes a good point in that QA/QC review is not the total picture to be used to determine if he stamps a document. It seems he is caught in a situation where another engineer can't keep up with his own workload.
In my state, the stamp is the professional property of the practicing engineer, not the company or management he works for - the responsibility for the use of the stamp first rests with the engineer.