Well it's like saying, "deer will never jump the string if you have a quiet bow"....

Blanket statements like that are always open to many exceptions. I've had complete passthroughs at 55#'s with the arrow stuck in the dirt on the other side with great shot placement, and I've had one deer with great shot placement at 67# that did not get a total passthrough. Bone/rib density can be a tricky thing. Of course shot placement is crucial, but I think it is bad advice to tell someone that you always should get a passthrough.