Lennon wrote that, many people have adopted it, he was wrong to write it. That said, I understand once a friend was visiting him and he had some sort of expensive collection of China plates, something like this. His friend said to him, “But John, you wrote that song, “no possessions”” and Lennon said “It’s just a bloody song”.
RE: Lennon said “It’s just a bloody song”.
In other words, Lennon is telling us not to take the words seriously... Unfortunately, too many people have made it the anthem for their cause.
There's an alarmingly high percentage of any population that will follow someone and atrribute God like attributes to them, for little or know reason. They call them charasmatic leaders (and they don't even really need charisma), like Charles Manson, or Hillary Clinton.