We recently had someone at our house to repair our dishwasher, because we suddenly started hearing a horrible grinding sound when closing the door.

Apparently we had bent one of the hinges! How? By overloading the bottom rack too many times. His advice was to load it ~50% LESS than we were. And don't pull the bottom rack out all the way when it's fully-loaded.

I can't tell if this is like general dishwasher advice, or our GE is a POS.

I think probably the latter. Either that, or your dishes are made out of tungsten or something. (If so, I'd love to see your dish collection. That would be rad.)