That's why they always dream of mass murder. It seems to solve so many problems.
Remember: "Utopia" is a world which translates as "No Where".
They want to immanentize the eschaton, not seeming to realize that it cannot be done.
Two quotes from C.S. Lewis:
Of all tyrannies, a tyranny sincerely exercised for the good of its victims may be the most oppressive.
The greatest evil is not now done in those sordid “dens of crime” that Dickens loved to paint. It is not done even in concentration camps and labour camps. In those we see its final result. But it is conceived and ordered (moved, seconded, carried, and minuted) in clean, carpeted, warmed, and well-lighted offices, by quiet men with white collars and cut fingernails and smooth-shaven cheeks who do not need to raise their voice.
Taken to the logical conclusion:
The national IQ bell curve profile would move 50% to the right,
Religious tolerance would return,
Chicago, New York and San Francisco, in fact most major urban areas, would be deserted examples of the "After Humans" program,
Still looking for the downside, here...