How to negotiate with collaborators on adjusting procedures to interdisciplinary projects?
It seems to me that the problem lies on a psychological aspect of their lives and your way of questioning is triggering this response on them. Maybe they're insecure about their academic formation or have been challenged in the past in a way that made them develop a very defensive stance when questioned. My suggestion is that you change your way of obtaining this info to a more friendly one. usually lowering your guard creates the same behavior on others. You could go for something like "I have no knowledge about this. Could you please teach me X? I feel it's important for my formation."