I don't think there is anything wrong in 'pop' when the work is intended to be popular. I expect the biographer to verify her sources but as a reader I'm not going to go out (generally) to verify them.

Things that happened, happened. Most of all when reading popular biographies I want to be introduced to real things that happened, and if some of that draws my interest, I can then dig in to more academic sources.

The popular biographies offer the '100 feet' view over their subject and the society in which they lived in, and should not be disparaged if they succeed in doing that in a readable and entertaining manner.

Yeah, I just think 'pop' is a good word to take down something seen as a comprehensive work when it's more of a '100 foot overview.'

That's a rare thing, though. The adjective should probably be used neutrally way more often than derogatorily.