By Daniel Kline The cruise lines have slowly returned to normal, and now, another covid rule has been dropped. Cruise lines have suffered perhaps worse than other businesses during the pandemic. That’s because the Centers for Disease Control (CDC) has more control over cruise operators than it does airlines, concert venues, or really anything else. The reason is that Royal Caribbean (RCL) – Get Royal Caribbean Group Report, Carnival Cruise Lines (CCL) – Get Carnival Corporation Report, and Norwegian Cruise Line (NCLH) – Get Norwegian Cruise Line Holdings Ltd. Report operate as foreign companie…