If Kanter had scored 15 pts in the game, that would be much more meaningful.
Use any criteria you want to define who you think did well against top HS guys. The conclusion is the same: doing well means nothing when it comes to NBA success or even making NBA 3d string roster.
No one is arguing that it automatically does. It's just ONE data point which should be analyzed when evaluating him. But what you seem almost to be arguing is that having success in that game somehow proves that Kanter is going to be a bust.
That "ONE data point" is the centerpiece of entire evaluation. The only time Kanter played against somewhat decent competition. If you put this "ONE data point" in perspective, as I just did, you are left with nothing to project the guy top 3. That does not mean he is bust, but it does make him a HUGE risk at top 3, without appropriate reward justification. Much like a lottery ticket.