I'll never understand why people argue about basketball without knowing what they're talking about. Simply stating "oh, but Ainge said X" and "Ainge said Y" is not a proper argument, from my point of view.
With all due respect, I'm a lot more inclined to believe Ainge's opinion than yours. You've watched a bunch of games on a not-very-good video feed from nba.com. He has direct access to the kid's practices, as well as game footage from now all the way back to his KU days - and probably even from high school, if he wanted it for some reason.
With that said, I think there's a lot of difference between 'ready to contribute defensively in the NBA' and 'ready to be a defensive ace in the NBA'. People bite on shotfakes in the NBA all the time, but it doesn't mean they aren't good defenders. Tony Allen is notorious for it, yet he's universally regarded as at least a good defender, and most consider him very good. With all of this said, though, I took Ainge's comments to mean that he could hold his own defensively in the NBA, but currently his offensive game isn't enough to get him minutes. I don't necessarily think Danny was endorsing JR seeing the court in a meaningful game.
Sorry to break it for you, but there are three major problems with that kind of argument:
1) Sometimes Ainge lies. It's part of the job. For example, have you ever heard a manager in the draft night saying bad things about his pick?
2) Sometimes Ainge is wrong.
3) It's a formal fallacy:
http://en.wikipedia.org/wiki/Appeal_to_authorityI've presented my arguments in defence of my position, explicitly pointing out some of the moves that Giddens doesn't master. Either you explain what I'm seeing wrong or there's no point on carrying on this conversation; it's useless to debate with people whose only argument is an Appeal to Authority.
Post-modernism has arrived to basketball.
"Mental game" is a cliché used too often.
Every player in the league would disagree with you. Ask MJ if mind games played a role in his game. Ask Paul Pierce the same question. Ask Rondo, or Baby, or even Ray and Eddie if confidence is important to their jumpshots. Ask any player if homecourt is a significant advantage. These are all aspects of the mental game, and they are very important to basketball.
As for the topic relevant to the comment, Giddens has admitted that he's nervous and his legs feel like jelly when he steps on an NBA court. Is this not noteworthy? This is one of the biggest reasons that Billy got occasional real minutes this season while Giddens saw 7 minutes in garbage time: Walker showed the ability to keep his composure at the NBA level, and JR didn't. I really don't think this side of the game can be dismissed as a cliche.
First, you are using a strawman argument. I didn't say that the mental part is not important; just that it's also a cliché used too often, mostly by people who don't actually have the tools to scout players from a fundamentals perspective and just throw the "not mentally ready" gimmick.
Second, and more important, I'm watching Giddens playing in the D-League. I'm identifying flaws in his game when he's playing in the D-League, not in the NBA. How exactly the fact that he's nervous in the NBA is relevant for this?
You theory is that the fact that he's not mentally ready to play in the NBA is what causes his deficiencies in terms of individual skills when he plays in the D-League? Quite interesting, to say the least. You should write a book on this, the coaching community around the world would be shocked.