Yeah Charles Manson, Jim Jones, David Koresh, Warren Jeff's et al all compared themselves to Christ too.
Cult leader 101 - you use your charisma, narcissism and manipulatation to gain followers. You have already committed crimes and or/go on to perpetrate crimes against your followers. Often of a sexual nature.
You know it's a matter of time before the world finds out. So what do you do? You tell your followers that you love them, care about them, want to protect them from the bad world and to do all that, you have to tell them truths about the world. And you are the only one telling them the truth.
Then you tell them or at least hint or drip feed that this is a dangerous thing to do because it will make the bad people controlling the world very angry.
And that means the bad world will come for the cult leader and by way of that, come for the followers too because the most righteous/enlightened/chosen will always be persecuted. Told they're stupid or uneducated or conspiracy theorists or brainwashed. The world wants to silence anyone who speaks the truth and want to hide the truth from the wider world.
And you tell your followers that the bad world will tell them terrible things about their leader. Things they won't want to believe. But you know what it means? It means everything the leader told them before must be true. This confirms it. They must be truth-tellers and getting close to exposing these truths because they told their dear followers that this is what happens to the most righteous/enlightened/chosen. That the bad world comes for them, tells lies about them, shuts them up, puts them in prison or kills them.
Russell just read some cult books, had the necessary disordered personality and added additional heinous crimes of popularising deep-necked tops for men.