I'm not a huge Nirvana fan, but I think the thing with Kurt wasn't that he hated the idea of being popular, or even that he hated popular musicians. I mean, yes, he loved the Melvins and Vaselines, but he also loved The Beatles, Neil Young, and Bowie for Christ's sake. What he hated was the amorphous idea of using being popular to push phony bullshit, which is why he openly feuded with Guns N Roses (mainly Axl), whom he thought were basically bloated jokes by the early 90s. And as Nirvana blew up, and the musical subgenre he was the figurehead for became more and more commercialized and diluted into something that approached phony bullshit, it gnawed at him. Frankly, doing an acoustic concert where he could play some of the songs that were at the foundation of what he was going for with Nirvana was probably, in his mind, the least "sell out" thing he could possibly do at the time. It was bringing his music away from the commercialized version of "Grunge" that had taken over America by 1993 and back to its fundamentals. "Here" he was almost saying, "stop listening to this music I wrote because it's popular, listen to what the song actually is without all that extraneous shit laid on top of it."
Anyway, so it doesn't surprise me that he wouldn't want to be in a Hollywood production about Seattle as a background to some rom-com story, which is probably how he viewed the proposition.