Fads, Marketing, and Fashion versus Practical
I've noticed gentleness becoming more of a selling point for washers the more HE washers don't clean as well. Maybe in the same way jean makers are recommending babying them as they make them from cheaper materials.
I actually work in my jeans. I wash them on the Heavy Duty cycle and warm water. They eventually wear and tear around the knees, which is the biggest wear point. In fact there often seems to be little wear any where else by the time the knees tear, so it appears to me most of the wear comes from bending and kneeling during actual wear, and little if any from harsh agitation, unless somehow the washer knows to only attack the knees because that's where I get the most grass stains and such.
I don't know about Levi's, as that's a brand I see specifically mentioned on this forum sometimes. I haven't worn them in years, it seems they've become more of a fashion brand than work pants, so maybe they need special care. I usually just get the cheap brand when they go on sale for $10 at the local farm and ranch store, or Wranglers. Both seem to be a much better value, and I've never seen them disintegrate in the washer, not even in the Heavy Duty cycle of the ferocious top loader.