I guess Alan Alda was not available...
The Left does not approve of the sentiments found in Jack Reacher. So they will use any actor to try to defuse it. If they could get Alan Alda to do it, they would.
My guess is the best actor for Jack Reacher in the Left's eyes would be Woody Allen.
Tom Cruise is not it, you need an Arnold Swarchsnegger or someone with Rippling Muscles to do it and Jack Reacher is known to eliminate his enemies with his bare hands.