It's not so mysterious, if you think about it.
Folks on the left tend to think that we should live "collectively" -- sort of like insects in one great big hive.
A great many left-leaning folks (especially here in the USA) still remember (with fondness!) the '60's, with rural communes where everyone was "back to nature", and people thought they were "one with Mother Earth".
THAT's the sort of place folks on the left would take us to -- the sort of place Columbus found where he first discovered ther New World. A place where no fossil fuel -- and no nuclear fuel are consumed.
Rather like America in the 1700's -- or parts of the world now.
I'd like to see the whole bunch of themk become 'one with Mother Earth' - if you get my meaning