I don't think it's a weak argument at all. Where are all the Lynch fans who cried out in discontent at his presence? There aren't any. Not that I know of, anyway. I just sort of grinned and thought it to be in line with Lynch's unique way of doing things.
The question wasn't directed at me, but I'll answer it anyway:
No, he doesn't make his point with the Billy Ray Cyrus thing. Billy Ray Cyrus appearing in Mulholland Drive is par for the course as far as Lynchian bizarreness goes.
Personally, I think Lucas bent his wookie sometime during the...