In WT theology THEY ARE the Kingdom.
So, they have preached faith in themselves as Gods channel of communication. In their own deluded minds, they have preached the “kingdom” in all the inhabited earth.
Of course this is a gospel unknown to the apostles and so they fall under the curse promised in:
Galatians 1:8-10 King James Version (KJV)
8 But though we, or an angel from heaven, preach any other gospel unto you than that which we have preached unto you, let him be accursed.
9 As we said before, so say I now again, if any man preach any other gospel unto you than that ye have received, let him be accursed.