This overlooks that 100% cotton jeans will break down when they are discarded (unlike polyester and nylon). A good pair of jeans can be mended and worn for many years instead of a new pair every year. Jeans can lead a very useful “after life” as insulation or be recycled into new fabric.

It also ignores the chemicals and energy required to turn beechwood and bamboo into wearable fabric.

I don’t know what the solution is but natural fabrics aren’t the enemy.

Well how do we know that any scale at all is right?

My lab has weights that get calibrated against a NIST standard annually. We use those weights to perform daily quality control that our scale is accurate (to +/- 0.01g). If the quality control fails then we recalibrate the scale.