You know such contradictions are what gave rise to over 41000 Christian denominations. Such scary statements will not come from Jesus who said: “I am gentle and humble in heart, and you will find rest for your souls. For my yoke is easy and my burden is light.” (Mathew 11:28-30) Such statements come from humans who are bankrupt of ideas, hence resorted to the easy way of instilling fear in humans, as JW GB does!
Jesus’s original style is “Whoever has ears, let them hear.” (Mathew 11:15) In other words, whoever is not willing to listen, there is NO COMPULSION to listen to him. Let then do what they like and reap the consequences. (Mathew 23:12; Mark 4:24) This he learned from his heavenly Father. (Mathew 5:44-48)
When there is a cancerous growth in one’s body, he may prefer to remove that particular portion, rather than abandoning his whole body. Similarly, don’t discard the Bible just because of some contradictions you find; there are very precious things in it—hence take only what is reasonable and beneficial from the Bible. (1Thess 5:21) When Jesus said what is in Mathew 23:9, he was pointing to an eternal truth which everyone unconsciously subscribes to. Statement also implies humans (unlike JWs feel) can bring God’s Kingdom on earth by their effort, if they choose to do so. If something is not intended to be practiced, why should he make such statements?!
If one CHRISTIAN ruler (in a great Hindu-dominated country) can do it in his State means other powerful Christian rulers surrounded by Christian rulers can easily do it! (Americas, Europe and former USSR and Australia … bulk of the globe is occupied by Christians!) What is the difficulty for followers of Christ to follow Christ?