Agreed.


Thread failure is evidence of user negligence. It is your responsibility to make sure extractor nut is properly resting on cranks’ base before proceeding to extract. I know sometimes you have metal shavings (or rock granules for that matter) that can get it stuck tricking you into believing is fully engaged.
When you fail to do so, sharing force are then exerted or transferred to the threads which are not in any way designed to support this load.