Well, that may or may not be valid - but consider the details of hunterdan's experience: the truck and the skidder were both there a minimum of two weeks, probably longer. The season was unusually wet, and the ground boggy. Skidders weigh far more than even my four door SR and run massive tires that weigh hundreds of pounds apiece. The chains strapped to the rig had links/ rings that were larger and taller than might be used on our trucks, and were pressed into the soft, wet earth by several tons of heavy equipment that, in all likelihood, was driven in a crisscross pattern over the same small patch of land for hours every working day. Trails, by contrast, are used differently - a truck passes through a length of track, and possible turns around to complete the route backwards. On trails that loop, the trail is only impacted by vehicle "x" once per excursion.
I think the more I dig into this subject, the more I realize that those who oppose the idea of tire chains on the trail typically have never used them at all; the ones who sing the praises of chains for the ballsout traction they provide , backed up by actual experience, normally reinforce the notion that chains don't rip trails unless an irresponsible moron is behind the pedal.