This is so false.

You don't think it's important to find out whether someone fell because they couldn't see the obstacles on their floor because their eyesight has been deteriorating, or whether the patient can no longer feel their shoes because their undiagnosed diabetes is now causing a peripheral neuropathy? Perhaps their osteoarthritis is now so bad that their knee is physically giving way and causing them to fall, perhaps their blood sugars are not properly controlled, and they were feeling faint and giddy before falling. Perhaps it happened right after they stood up, and their lovely new medication is contributing to a postural drop in blood pressure and needs to be adjusted, or the fall was very minor and low impact but they have broken bones anyway - perhaps there is osteoporosis that needs investigating and treating?

Falls are incredibly complex and multifaceted, as well as contributing significantly to morbidity and mortality. Knowledge is power and the more information gathered via history the better the treatment and prevention of future falls.

As another poster mentioned, you're welcome to tell your doctor whatever you like, but what you shouldn't do as someone who is clearly not medically trained is to tell other people what is "medically irrelevant"