Perhaps more importantly though, believing things have objective value often leads to very real errors in the evaluation of particular circumstances.
You believe that you have no errors if you completely evaluate every thing ONLY from the perspective of subjective value?
No. That would be a logical fallacy. That X leads to errors does not imply that errors can't be made under Y. Believing that there are 11 inches in a foot will lead to faulty construction but it's still possible to build a faulty wall with functional measurements, of course.