Its not Kershner's fault the film went overschedule and overbudget. The director doesnt concern himself with those issues, that is the producers job. Yes, it is easy to see WHY Kurtz let the production decompose so much, because he wanted the material to be good--but it was a luxury they literally couldnt afford, and Kurtz was EXTREMELY irresponsible in doing this, especially when you consider it was Lucas' personal funds and he wanted the show to move and be finished. Lucas is lucky that he had more star wars fans than he realised.
In any case, this has nothing to do with Lucas praising or bashing, its simply Kurtz getting creative credit on one of the greatest films ever made when he is one of the worst professional producers i have ever heard of.
And BTW, what the hell are you talking about? Lucas' smug smirk? He seemed very grateful to get the award and i think this vitrolic Lucas bashing gets out of control sometimes like this, being labelled a "smug jerk" and that he makes you sick. What the hell is up with that?
Anyway, you dont have to interpret Kurtz-bashing as Lucas praising. Kurtz at least can objectively be bashed.