If this were true, no one would be riding bikes with rigid forks (road bikes and non-suspension hybrids), which in my estimation are at least 75% of the commuting bikes out there. If you are overweight and put too much weight on your hands and wrists you may feel the larger bumps more with a rigid fork and develop pain or injury, but this is not an issue for most reasonably fit riders. Under typical commuting conditions on roads and MUPs, the suspension actually does not move much, if at all, except when climbing out of the saddle, which is when you really don't want it to move.

I ride a carbon fiber road bike and commute on an aluminum mountain bike with a rigid steel fork, and there is not much difference in ride comfort on the same roads and MUPs. It most definitely has not increased the strain on my arms, wrists or hands. I changed to a rigid fork last winter, and hung onto the suspension fork for a couple months, but trashed it when I decided there was no going back. BTW, I put in 150 miles a week at max tire pressure.