Work (Force x Distance) definitely varies with cadence. Force varies with crank position but is modified by the efforts of the rider. But the point is that any human has a maximum amount of force that they can apply. And that force translates to forces on the bottom bracket and axle and hub and frame ends via chain tension. And chain tension is proportional to gear ratio. And the typical mountain bike or even most road bikes are equipped with gear ratios which can provide much more force than a typical fixed gear.

Therefore, skidding stresses the frame less than using a low gear. Also skidding results in less bending moment on the seat stays than braking does.

It really is the increase in awesomeness which is the major effect of skidding and we all know Newton wrote how awesomeness wears out tires faster.