I have as much affinity for the song “Do They Know It’s Christmas?” as the next Gen-Xer. I know I’m not alone in the nostalgic resonance of the echoing, opening chimes, which will forever harken back to the rush of the first view of the video, the slow-motion assembly of some of our favorite artists—Sting, Bono, George Michael, Boy George, Phil Collins, and more—all coming together under the name of Band Aid, just in this precious first moment, for a greater cause. It was 1984. We were told we, the listener, had the power to help the starving people of Ethiopia. All we had to do was purchase “Do They Know It’s Christmas?” The single went straight to No. 1 in the U.K., where it stayed for five weeks. Band Aid sparked 1985’s Live Aid, the most successful fundraising concerts ever (there were...