Hi,
I have a different view. Sy you don't have to pick one over the other. You dont have to even place who is the priority here, your gf or your parents.
They are visiting you for 2 weeks and they are your parents so of course you have to accommodate them while they are there and soon enough they will be gone and you and your gf will have your life back. SO I think your gf needs to be more understanding of your relationship with your parents. And you can tell them to leave their condescending talks to when they are away from your house because it embarrasses you in front of your gf.
When my in-laws come to visit us I know that the visit will pass soon I try to not get so frustrated and just do what I have to do.
Good Luck.