Service members who joined up when the first full-length episode of “The Simpsons” hit the air have been eligible to retire for about five years. And while the long-running animated series rarely dabbles in military-themed humor, it’s tough for any scripted television to go a quarter-century without somebody stealing a tank, somebody else entering into a blood pact over World War II plunder, and somebody else becoming a red-team leader in an Army war game through a series of inexplicable circumstances. It’s simple math. FXX recently secured the rights to the show’s massive back catalog, and it’s celebrating by airing…
