Why can't it be both at the same time? Vonnegut was both a great thinker and a great writer (the former is typically a precondition for the latter).
Remember that his exemplars aren't great Randian industrialists, but like... dancers. Artists. Quietly intelligent men like himself. Vonnegut isn't saying "the strong should triumph and stand on the backs of their lessers and dominate the world" but rather just "let great and beautiful things be great and beautiful".
And there's the subtle misogyny that our hero is smart and his wife is a bit dense and happily accepts their dystopia. I love Vonnegut, but that fits with his writing through and through. Vonnegut's women generally... aren't great.
Yes, letting greatness be victorious has kind of a conservative bent because it also implies letting the losers lose, which runs runs against progressive ideals that Vonnegut seems to hold of making sure everyone is taken care of. I think Vonnegut was the kind of man who could hold both those thoughts in his head at the same time.
We contain multitudes.
In general, it's a cute story within Vonnegut's body of work, but anybody who fixates on this one piece... it's kind of a red flag of "I would do great and awesome things if only the bleeding heart liberals stopped holding me back!"
Let's be brief and accurate instead.
Because they have genders, right?
Sometimes a cigar is just a cigar, not a statement of identity politics.
With that lens, kind of reflects the 20th century nerd experience; The tall-poppy nerd kid who is "handicapped" in school and, escaping into adulthood, becomes an arrogant and overbearing prick.
I have found it to be multi-layer, with an obvious layer at the top, and other stuff for those who delve deeper.