From the guidelines: On-Topic: Anything that good hackers would find interesting.
My guess is that caludio believes that good hackers would not find this article interesting. I somewhat agree, as I feel that article adds little to what can already be found in the cURL man page. Having said that, I do think there is worth in having good examples, which this article certainly did.
It's a little disheartening to see this at the top of HN though.