Wrong Jon. These guys aren't professional athletes, they're baseball players. Look at Mike Piazza: Strong arm(if he was throwing from the OF, you'd be impressed), 20+ years catching experience and he threw out 12% of basestealers this year. Why ? His footwork, weight transfer and release suck. Do you really believe that the average major league player, much less Henderson and Phillips with minus arms, would throw out a few runners ? There may be a few guys with great arms, who've caught growing up, who would throw out the slowest runner 5% of the time.
This is not the same as a football player punting. Catching requires a unique set of skills, polished to the highest degree, to be even an average MLB catcher. The better ones add on truly superior physical attributes that seperate them from the rest.