You know it's an overstatement when i say "pencil straight", stop trying to nitpick.
The point is, everyone can throw a fastball with little to no movement if they so desire, Mr. Leo Mazzone. People having "so much tail" they cannot control it is an outright lie. I've seen loads and loads of young left-handed prospects in my lifetime and i've never seen this phenomena you speak of. And also, you say a cutter is not "That bad on the elbow" because "you threw it when you were 10?" lolwut?