It seems likely they will treat you like crap if you go, and like they will treat you like crap if you don’t go. I wouldn't rest your decision on seeking their approval and acceptance.
Handling them will require solutions that do not include changing your healthcare to please them - like setting boundaries and having a stronger sense of self that they can't rattle as easily.
What would it be like for you if you went? Do you feel like you've got the skills and stability to handle whatever they throw at you in a manner where you don't contribute to a negative experience for your daughter? (She may still have a negative experience because they sound like crabby jugdey people, but that's not under your control. Only your actions are under your control.)
At the end of the day, the graduation is about her. Will your being there, in the place you are at now, enhance her celebration, or detract from it?
Will you be able to be exposed to crappy judgemental comments from them, and stay safe to yourself, and cool, calm, and collected around them?