The PPH is a resource and just that: a resource. It's a good one, especially for a few things, but it should be treated just like any other resource. The PPH is not some kind of Bible or Quran which is inquestionable and perfect like some people here seem to think.
If the PPH is so perfect, please tell me why D is still listed as "B", why the PPH claims he sells Dolaltol while he does not and why the listed prices don't match what A and B/D are really charging, even in the newest update. These are 3 errors on just one single page.
The section about known persecution of N importers hasn't been updated for ages.
Also, the contents of the PPH are debatable. For example, a Dutch pro-choice advocate who wrote his own book about humane ways of dying publicly said on TV he opposed the inclusion of SA/SN in the PPH a few years ago and recommended people (on TV!) to look for N instead.
And there actually has been a shortage of N in the US recently, although some individual purchases won't really affect that:
www.aaha.org
About the original question: by buying N you're making a Mexican drug dealer rich. Is that ethical? Probably not, but there's also no alternative to get your hands on the product.
What can we say about the ethics of the pro-choice organisations though?
- Exit International discriminates both on age and mental suffering. They charge inflated prices for simple barbiturates tests and often refuse to (fully) refund the money if someone under the age of 50 orders their products.
- Pegasos in Switerland charges around €10.000 for a humane death.
- Coörporatie Laatste Wil, the Dutch pro-choice organisation who came up with SA and SN was planning to sell 2 grams of SA for €180 to their members, while the actual value was worth less than €0,10. At the time both SA and SN could be legally bought by individuals in The Netherlands. They claimed they did this to save money for the lawsuits that would follow.
The ethics around all of this is something that is certainly up to debate and everyone is entitled to their own opinions.