This is the full quote, according to Parenti:

Left anticommunists remained studiously unimpressed by the dramatic gains won by masses of previously impoverished people under communism. Some were even scornful of such accomplishments. I recall how in Burlington Vermont, in 1971, the noted anticommunist anarchist, Murray Bookchin, derisively referred to my concern for “the poor little children who got fed under communism” (his words).

It’s literally a personal anecdote claimed by Parenti, so I don’t see that being corroborated.