I've started to see a bit of this lately, like cars they are worth more broken up.
It's a real shame that people do this, and I really struggle to see anyone paying good money for these bits, but hey it takes all sorts!
To be honest I think there is a bit of a market for this stuff - think of all the vintage stuff you have (or have had) where one bit is broken or missing and you'd rather just find an original part to fix yours rather than buy a new one - it is a shame when you think of a complete toy being broken up but certainly a market. Lego has always been that way, Figure collectors have always been selling sets without figures and again for folks that do a lot of custom building it's a great way to get a lot of pieces (often specific) without the need to buy RRP sets or bricklink orders etc. but again it is a bit of a shame when sets get split up, although I am guilty of buying both figures I want but from sets I don't and sets without figures where I want the parts but not figures - There is a market for everything