Thanks for the insights, IndiReloaded. These mean a lot to me!
Yes I always assure my gf that I love her no matter what, and that I am on her side. Due to her pain, she almost left me, many times, because according to her, the pain is too unbearable. But she said the reason she's staying with me is because she feels how much I love her, and that she trusts that I'm on her side. (Although, she occassionally gets jealous or even angry whenever I do things related to my mum, such as driving her to do some grocery shopping.)
Your idea of getting my gf to do nice things for my parents is brilliant, and in fact I've thought about it a lot. I wish it were that easy though. It's unfortunate that my gf is the kind of person with a black and white, all or nothing mind. When she loves someone, she loves intensely. Accordingly, when she hates someone, she hates intensely.
She said that my mum's assessment (on that list) hurt her like crazy, especially the parts about her dad's hepatitis (she feels incredibly insulted). And she feels totally betrayed and cheated, because my mum pretended to be nice, and even hugged my gf on the day we took her to the airport when she was going back to her country.
She even told me she hates my parents, and told me that if it were up to her, she wouldn't let my parents come to our wedding, although she said that since they are my parents, she respects them because of me, and that she won't actually prevent them from attending.
But thanks for this huge tip though. I'll see if I can get her to be more on the grey side, instead of black and white....