No, can't see the problem with the spot-elder who the Manchester Rambler never got round to marrying. Presumably there's an specific reference of some kind that lies behind it. But anyway, I can't see how it "ridicules the whole purpose of the song." Ewan MacColl was never noted for his sense of humour, couldn't accuse him of frivolity or excessive lightness of touch, and I suppose this is about as light as he gets. Cheerful rather than funny. But pretty good juvenilia.