Having a different opinion on a situation, and wanting to save you from further pain are not the same as thinking you are an idiot or making you look like an idiot.
I can appreciate how invalidating their behaviour feels. I can understand how much you don't want to hear it. I can also appreciate how hard it is to stand by whilst someone you love desperately hangs onto a hope that doesn't seem to come into reality, in the face of all evidence to the contrary and NOT say something, especially if asked or the person I love is describing their pain or obviously unhappy.
after I left stbxAH I have had ongoing contact issues with him related to our children, I was describing my dilemma to my mum and step-dad. They listened to my fears, gave me a hug and at the end, although I could tell my mum was just itching to give me advice, she didn't, my step-dad said "I know whatever you decide will be the right decision" - how perfect! I felt heard, supported and validated: but they are human and sometimes the pain of my children's contact situation is too much for them to bear.
The other thing that struck me, although I know your post was short, was you didn't describe a point where they actually said you were an idiot. I often, especially when really stressed, attribute motives and thoughts to other people that are actually some of my own. If I fear I may be an idiot for doing this, and someone doesn't agree with my actions, I think they beleive I am an idiot.
This negative self-talk and projection is something I have to work on - it may well not apply to you (())