I think people who like rare steaks just talk about it more because it's the "right" way to prepare the "best" cuts. A $200 steak is just going to be most flavorful when it's on the rarer side. But its just a signaling thing if you're talking about skirt or flank.
Same question could be asked "why does everyone all the sudden love whiskey neat so much?" - they don't, its just that the whiskey folk talk about it conspicuously.