Well who else is going to answer it? The civvies will probably have an idea but weren't involved at all. I think we all would agree it was for separation purposes of some sort, and not just for spite. It doesnt have to be a busy airport, you just have to be in the same place at the same time. You might be the only two aircraft in the sky. If they'd refused his take off clearance until the Herc had departed, would he be happier? They just got him out of the way of something bigger, heavier, and faster, and then let him go. It was a few minutes holding 35 years ago. Move on.