[racket] Thread creation slow?

Hi all,

On IRC the other day, this blog article about Racket came up:
  http://cxwangyi.wordpress.com/2012/07/29/chinese-whispers-in-racket-and-go/

In it, the author shows a program that creates many threads & channels
and then daisy-chains some communication through them. The Racket
version is significantly slower than the Go version (1 min. vs. 1 sec.).

Is there a performance bug with thread creation here? Alternatively, is
there a different way of coding the example that would make it faster?

Cheers,
Asumu