I generally agree with you about not setting jack stands on gravel. However, I do it all the time in my driveway with no worry. A few years ago I had a new concrete back porch poured. When the contractor finished the porch he asked me if he could dump his leftover gravel on my gravel driveway. My driveway was needing new gravel anyway and I recognized the gravel he had. It was medium-size gravel with fine dust mixed in, sometimes used for roadbed base. Since that gravel was added and packed down, my driveway is hard as concrete. I have set my car or truck on jack stands many times, even when raining and those jack stands are solid and never sink into the gravel. I have a F150 sitting on jack stands on that gravel for several months now and no problem. But, you are right. I wouldn’t do that on a normal gravel driveway.