R&P: Is it me or is this song sort of describing communism?

You may very well be right. It's hard to tell the exact context with which Lennon was using with these lyrics. Lennon was very gifted at conveying lasting impressions upon the listener using very simple words, but often times phrases that carried no one specific meaning. It was up to the listener to decide what he was saying and generally the listener didn't decide because the melodies were very catchy and effective. We all got the overall impression of a good cause or a righteous thing going on when observing Lennon and those who scrutinized or tried to pick apart the lyrics for meaning only added to the mystery of it's intent. No wonder he was so successful as a recording artist.