Jesus also told Simon Peter to "Get behind me, Satan," in that very same chapter of Matthew, when Peter suggested they shouldn't allow Jesus' sacrifice to manifest.

Christ restored our ability to have a right relationship with God. Our failings in that were the only reason the Israelites set up a monarchy in the first place. To believe that God needs an earthly monarchy in order to organize His Kingdom would be to say that God is incapable of reaching us personally.