Hey everyone - I just wanted to bump this thread up because in reading the rest of the CB - it's just so amazing how HP relates to everything!
I agree, JKR touches on some pretty universal situations in the wizarding world.
Regarding the house elves-- I believe they are magically controlled/bred to be happy to serve no matter the situation. I doubt the Blacks were kind to Kreacher but he is fiercely loyal! In my mind, the only explanation for this is either magic or mental instability.

I remember reading that Harry was told that house elves are bound magically for their own protection-- or something along those lines. Dobby, even though he desired freedom, loves work and even begged Dumbledore for less pay and fewer days off.
I always thought Hermione's SPEW knit hat crusade was odd. How can the house elves clean (including laundry/picking up clothing) without accidentally being set free? Or do wizards do their own laundry but allow house elves to clean the toilet?
Picking up a stray hat seems too easy and Dobby would have been freed long ago if it was as simple as getting into Draco's sock drawer. I had a problem with Harry tricking Lucius into setting Dobby free-- Lucius was unaware and it was essentially an accident. I always thought the presentation of clothing was a formal event-- not a dirty sock tossed to the side.
It is interesting, though, that the house elves won't clean the Gryffindor common room because of the hats. I don't know if it is a fear of being set free as much as it is their overwhelming desire to work and be happy working. And I would think that only DD could set them free but maybe, being residents of Hogwarts, the students wield the same power-- the house elves do obey students as evidenced by the twin's forays into the kitchen for snacks.
I have heard some crack theories that make JKR out to be a racist due to her enslavement of house elves. I don't buy into that.