I think there's a fallacy where someone points out one instance of a larger trend which will, when taken to its logical progression, lead to an undesired effect; and then someone attempts to rebut the claim by pointing out that the trend has existed before and the undesired effect hasn't happened yet, so any concern is nugatory. I'd call it the grippery slope fallacy, complement to the slippery one: we haven't fallen down the slope yet, so we can't fall down it. What if an individual instance of ignorance is acceptable because people still need to have understanding in other areas, but if all understanding everywhere is eliminated then we all suffer?