Appeal to tradition
According to Discovering the World through Debate, an "appeal to tradition" is "A fallacious argument made when a debater argues in favor of a particular action on the grounds of tradition rather than on the basis of that action’s merits" (246).
Trapp, Robert, et al. Discovering the World through Debate: A Practical Guide to Educational Debate for Debaters, Coaches, and Judges. Third Edition. New York: IDEA Press Books, 2005.