Not real familiar with all of DeFranco's stuff, but I wold bet it is more dealing with impingement on the rotators and all the muscles in the cuff. Ha, I think Ferrigno was big on half rep pressing!? (did not look like it hurt him!?)
Honestly, I never had much if any problems with OH pressing, it was always more BP's or the angle the shoulder hit at the bottom of a BP.
I know some guys feel that hyper extension of the shoulder joint wrings out the little muscles over the top shoulder bone (acromion!?) I did not look it up.
A good book to get, which I think may have been reprinted is, The Seven Minute Rotator Cuff Solution By Horrigan. It is an in depth look on all the little muscles that hold and support the shoulder and is a good read on what exercises to do to rehab and keep the joint healthy.
Probably started the L-flye or Shoulder Horn movement for many lifters.
Personally, I am a big believer in full ROM moves, so as to not develop shortened moves, that later need aggressive stretching to get back some good mobility and keep from further injury.