To each his own when it comes to training. You don't like the choker chain, I don't like all the bells & whistles. We wouldn;t have a single K9 officer working today if the oly training he had was a nice pat on the head. These are GSDs - not toy poodles. No harshness is needed. But yes, one must be firm. No-nonsense when it comes to working with a 88-lb dog with big teeth & stubborn as an ox.
Treats, food, praise, clickers, choker chains, GL, ecollar --- to each his own. Do the Hokie-Pokie if it works. But I still think the trainer was well within his limits to correct your dog. How else will you - & subsequently your dog - learn?
What kind of collar does your dog wear? And all it took was ONE TIME of you holding the leash & then praising when the dog didn't knock your mom down? Well then heck - you're way beyond me cause it always takes me more than once to teach or correct a behavior. Congrats!