ANSWER: Marcus Garvey, a Jamaican, formed the religion commonly called Rasta (Rastafarian). The crowning of Ras Tafari Makonnen (Haile Selassie I of Ethiopia, also known as Prince Tafari before his coronation) as "King of Kings and Lord of Lords" took place in Ethiopia in 1930. The use of marijuana (pot) as a "sacrament," prescribed by the religion as an aid to meditation, is not a Biblical principle. The Bible also does not command the wearing of "dreadlocks" as a commanded hairstyle.
Some of the beliefs of Rasta are undoubtedly true, as no religion is entirely a lie. However, the black separatism and the hatred of whites engendered by this movement certainly are antithetical to the teachings of Jesus. Many view the belief in the superiority of the black race, as promoted by the religion, with skepticism. We are all equal in God's eyes, as Paul wrote that in Christ there is no distinction of race, economic class or even sex - all are one in Jesus (Galatians 3:28).
You asked if Haile Selassie was the highest honored emperor on Earth. Only a few million people, at most, revered Selassie, and there have been emperors who have had tens of millions of adherents (China's rulers, etc.), and since only a few outside of Africa (mostly the educational "elites" and "progressives" as communists like to call them) - were even aware of Selassie's existence. It is therefore not true that he was the "highest honored emperor" on the planet - even though he was no doubt highly esteemed by those who believed in Rastafarianism.
Marcus Garvey claimed that Ras Tafari Makonnen (Haile Selassie) was essentially God in the flesh, the second coming of Jesus, the Messiah and was worshiped as a god. Furthermore, quoting from a Rastafarian-related web site, the following statement is made.
"To greater represent the truth, Rasta rejects the Bible used by most Christians, opting instead for a 'black man's Bible' known as the Holy Piby."
Jesus, when he came two thousand years ago, was literally God in the flesh (or God dwelling in flesh) and was the ONLY begotten son of God the Father. Based on many scriptures, Haile Selassie was not and could not have been "god in the flesh."
Furthermore, when the TRUE second coming of Jesus occurs it will not happen secretly nor take place in a far-flung part of the world unbeknownst to the vast majority of humanity. The WHOLE WORLD will know when Jesus is coming back to earth, and that he is doing so with POWER and with the authority to set up the kingdom of God on earth (Revelation 19:11, 13 - 16).
Based on the Bible, one must reject Rasta and the beliefs of the Rastafarians.