Dragon is such a little bitch. He is the failure of his family. Garp is the legendary marine hero, so powerful he can spit in the face of the world government, and they can't do shit about it. The rival of the pirate king and yonko. Luffy is a rookie who in a few years reached the level of yonko. He doesn't even try to mess with the world government, and he is a bigger problem for them than dragon could ever wish to be. Than you have dragon. Runs away from the yonko like a little bitch. Hides like a rat all the time. He even gets overshadowed by his at best yonko commander level subordinates. He is a joke.