Man, that is really sad! When I look at models on a contest table I may see things that are wrong or not as good as they could be but I would NEVER say anything negative. I just quietly look at everything and not say a word!
I always say, no matter who you are, no matter what you do, there will always be someone in life that can do it better than you! Nobody's perfect!
When my son comes to me with a new model he has built out of Lego's, I may not really grasp what it is but I sure tell him how cool I think it is and how he did a great job! The next time he brings a new model to me, it's even better than the previous! I hate to even think how I'd make him feel by saying something negative!!!