Interesting. I'm not sure I understand entirely what demanding/challenging amounts to in this context, but - in my case - I find that at least some music to which these adjectives could easily be applied can work very well in the background.
For background music for working (which mostly involves reading and writing), I like more or less anything that can establish a certain mood or tone within my workspace, without also inserting itself into the foreground and irresistibly pulling on my attention. I find that anything embodying certain kinds of melodic structure - typical of, say, pop or rock - or that emphasises vocals (esp. if these are in English) is highly unsuited to this. But some of the music that works best is certainly 'challenging' on a standard understanding of that term, - say, free Jazz, or noise music - precisely because, like much purportedly difficult music, it lacks a strong melodic component.
For background music for cooking/cleaning, I like anything with a little bounce or oomf, and more melodic stuff works very well.
As for easy listening, considered as music simply to relax to, this can be more or less anything for me - difficult music can be very relaxing or 'easy', if that's what I'm in the mood for.
On the general point, though, against musical/intellectual snobbery, I'm with you entirely