May 1st (“May Day”) has been celebrated since the 19th century as International Workers Day / Labor Day (meaning, Internationalist Socialism Day). American socialists decry the celebration of an American Labor Day in September as a co-opting and mainstreaming of the radical holiday.
(Of course, the labor movement, so called, took the holiday from ancient pagans, but really, who’s counting?)
Calendar controversies aside, the question remains, Why Labor Day?
In 1999, for American Labor Day, Scott Kjar, then a grad student at Auburn University, asked “Why Not Capital Day?”