It's a straw man.
Vonnegut was a life-long socialist. He wrote for a socialist magazine in his youth, and his promotion of socialism is present in much of his work.
E.g. This is from "Dispatch from a Man without a Country," published in 2004:
‘Socialism’ is no more an evil word than ‘Christianity.’ Socialism no more prescribed Joseph Stalin and his secret police and shuttered churches than Christianity prescribed the Spanish Inquisition. Christianity and socialism alike, in fact, prescribe a society dedicated to the proposition that all men, women and children are created equal and shall not starve.
You
do know this, right? This is not news to you?
Quite a bit.
Vonnegut wasn't attacking socialism for allegedly wanting to force strong people to carry extra weight. He was making fun of conservatives who **cough** incorrectly proclaimed that socialism was about crippling individuals in the name of equality.
(On a side note, he was also taking a dig at television. Earlier that year, FCC Chair Newton N. Minow gave a famous speech attacking television as a "vast wasteland," saying it's a "procession of game shows, formula comedies about totally unbelievable families, blood and thunder, mayhem, violence, sadism, murder, western bad men, western good men, private eyes, gangsters, more violence, and cartoons." Minow's speech likely influenced the formation of PBS in 1969.)
While the story does lampoon the idea of handicapping individuals, your interpretation ultimately doesn't fly, because:
1) Vonnegut
supported finding ways to make outcomes more equal.
2) As with the left today, socialists in 1961
didn't believe in neutering individual ability to such extremes. That conservative critique was and is a straw man, not a legitimate criticism.
Well, let's just say it's not a suggestion.