I was trained to avoid dryfiing .22 guns also.
However, the Rugers are particularly well-designed. I remember reading about an automated fixture set up at the Ruger factory where they had production single-six revolvers repeatedly dryfired, and at last count, there had been several MILLION cycles snapped without any firing pin damage! These were the transfer bar actions.
On the other hand, I can think of several pistol designs (the Star Model B and BS semi autos come to mind) where the firing pin stop is also the retainer and firing pins routinely break from dryfiring.