Chronological Snobbery – this is when a thesis is deemed incorrect because it was commonly held when something else, clearly false, was also commonly held.

Although this fallacy is not as common as some of the others, I have seen it in action on a number of occasions.

Example; “Why must we accept medieval art as having any value when it emerged from the same period in which people burned witches and believed in fairies?” – from https://logfall.wordpress.com/chronological-snobbery/