Don't know him and no assertions cast.
My point is that he is Wrong to tell people never to handle in training, period. His rant centered around handling a dog after it widens it's hunt in the fall area. This is a different animal.
Also, handling "on" a mark is different than handling "to" a mark.
Too much Blowing and Recall could lead to Popping and other problems just like Handling.
For Handling "on" marks in training I would follow the 3 H's. First Help, then Handle then Hurt (so to speak).
I would rarely if ever handle a dog near gunners or in the are of the fall. If using remotes and a dog is in big trouble you may not have a choice. One big reason to use live birdboys.
On path to a mark depending on the dogs decisions there are many opportunities to apply 3 H's prior to dog getting close to gun or area of fall.