Right, but something being part of an algorithm isn't "random." The "RNG" system seems random to the player, but to Bungie it has a purpose. They have created said algorithm to drop different items based on many different variables, which we as the player will never truly understand. Which is why everything in the game seems so random. And Bungie has stated that Xur is in place for those who aren't "favored by RNG" (which is me).