Some of what you are saying has merit IMO, but I would say:
1) The reason I am comparing Griffith and Spooner is that I see two similar players - both young, both inexperienced, both what I would call offense first guys (different styles). I see one getting 15 min TOI per game playing in a situation (line 1 w/skilled linemates) that plays to his strengths, while the other gets 4 minutes in a situation that is testing the areas of the game that I would not call strengths (4th line against "grittier" competition. Maybe this is by design, which I could see, but 4 minutes? You have to give him at least double that IMO to get an accurate read on what he's doing.
2) I think that "the situation" is something that IS likely a combo of Clode and Spooner. Clode likes "his guys" and Spooner clearly isn't in CJ's penthouse now, and may never be. For his part, I would say that the B's have clearly asked Spooner to do some things better in order to get more TOI and get his game where they are comfortable with it. Hard for me to judge how he's doing because I don't know what they are asking him to do better? I guess what I would say is that we have seen this kind of thing before, and at what point does a team/coach allow itself to live with the fact that a guy may not be the best defensive player in the world, but offset that with his offensive contributions?
3) Blaming a potential confidence thing on the player instead of the coach is a copout IMO. If Spooner was a kid that lacked confidence all along and showed the same tendencies now, you would have a point, but I don't think that's the case. I am not a professional coach, but I have coached enough youth sports and been in the workplace long enough to know that the way Julien is handling Spooner is definitely NOT the best way to go about it. For whatever the reason, Julien has created an atmosphere (for lack of a better word) around Spooner that is more negative than positive, and is creating a situation where Spooner is thinking more about how he can fail and do wrong than succeed and do right. I think that the way Clode handled the preseason MTL post game (where Spooner clearly did a lot of good things) was one of the worst examples of how to treat a young player that I can remember. Coaches need to treat each player as an individual to get the best out of them. Some guys need a kick in the butt, some need a pat on the back. Spooner seems (from the way he has reacted) that he is more of a positive reinforcement guy, and I don't see that happening. That's on Clode and the B's, not Spooner. If you are going to spend a high draft pick on a player, do everything you can to bring the best out of them and maximize your return. At some point, some of these players become "lost causes", but how can we say we are there yet with Spooner? I just don't see the B's doing their best to put him (and by association themselves) in a position to succeed.