They are scared of risks and injuries, even though that is part of the game. Yet they left in the all common contact at home plate with a catcher and base runner. If ya can knock the ball out your safe mentality. Also, the runner must touch the base. Yet the 2nd baseman has the liberty of missing or simply coming close to the bag.
You make a great point about home: but the catcher is well-armored, unlike the SS or 2nd baseman. After reading the comments, I am convinced that if they did make the middle-infielders touch the bag, they would go through 10 of them every season. The ‘in the vicinity’ rule makes sense.
Have you seen the size of some of these guys? Really, they would be carrying the little shortstops off the field by the dozens.