It's called a computer bug because the first computer error was caused by an actual live bug.
@MrGoat et voilà, Admiral Hopper's journal:
https://learninglab.si.edu/collections/grace-hopper-the-first-computer-bug/Hct9v6KEXynTR20M
@MrGoat I think it would have been funnier if the first defect were due to someone having a sticky spacebar, that or just a full on PEBCAK error.
@MrGoat a moth.