[Updated] “Joy is My Armor” by Alex Ebert is no “Home,” and he’s fine with that. The song moves to a bass line that employs dub reggae’s offbeat motor, and Ebert repeats the title phrase until it takes on a life beyond the lyrics. Joy is a shield; is it also a weapon? And why doesn’t joy seem more joyful? Does the military context take some of the fun out of joy?