Many scifi writers are socialistic/utopianistic and many would support the greenie politics.
I recall the Dinatopia (Walt Disney & Hallmark) movie and subsequent tv series. It was nothing more than a socialistic utopian environment. Youths were eventually placed in ‘jobs best suited for them’ and similar ‘for the good of the community’ indoctrinations happened throughout.
That's because many of them, by definition, are divorced from the real world. They are writing about imaginary ones after all :)
Just like every other part of society, the idealism of youth eventually gives way to reality. Poul Anderson is a good example.