You're not alone. Countless people have said you shouldn't dry fire a .22 for the reasons you mention. Yet there are still those who say it isn't a problem as long as you don't overdo it. That said, the NSSF Rimfire Challenge rules specifically state you have to pull the trigger after showing clear. Ummm...this means you have to dry fire your .22 a minimum of 40 times during the course of the match (5 strings on 8 stages). I have to believe that even proponents of dry firing a .22 would agree this is what's meant by overdoing it.