Why is it so hard for men to listen to and acknowledge that some women, if not most, arent interested in giant penises?

I used to think it was just incels stuck in this mind set but alot of men tend to push for the idea and even if you try to tell them the physical issues with doing it with a large penis, they double down and say you are lying. Why? Why are you so invested in this idea? Im not even angry, Im just baffled.