The technology that they have these days is incredible. The introduction of PITCHf/x in 2008 (I believe) has really helped revolutionalize some of the advanced studies that are being done. One of the things I hear often from the critics of advanced metrics, UZR in particular, is the amount of subjectivity that is involved in them. Yes, there is some subjectivity, but IMO, they are far less subjective than the fans who say they prefer to trust their eyes.
When it comes to any player, you want to choose the one who is the best overall player. If that means that you sacrifice some defense, then that's what you do. So, I agree that a catcher that can hit well, has a great arm, and is an average pitch framer might be better than a great pitch framer who can't hit or throw. That was not my point. My point was that out of all of a catcher's defensive attributes, the ability to throw out base stealers is the least important.