I'd be more inclined to chalk this one up to miscommunication (the bad headline) and good intentions (editing the headline for clarity) than I would to call this outright censorship.
Perhaps it is non-obvious reading only the title, but the article did go on to clarify what the intent of using the word "porno" was.
My problem with it is that editing the title in this manner sets up an expectation for the reader, and could cause the reader to become upset when they see the actual title has the word "porno" in it. As I said, the article clarifies what I mean, but if someone is sensitive to the use of that type of language, then they may feel they have been duped into looking at content they wouldn't otherwise look at.
As I pointed out in the article, this doesn't appear to be a common experience. I couldn't find anyone else online complaining about Hacker News censoring their content. But, I wanted to make clear what my intentions were, and hopefully open up a discussion that could possibly lead to needed clarity on exactly what the rules of this community are.
Please, accept my sincerest apologies for my misunderstanding and for jumping to conclusions. This article was not written out of malice towards Hacker News, but rather as an attempt to bring clarity to what is and isn't accepted in this community.
I've added a note on the post apologizing for offending anyone, and inviting anyone who would like to discuss the issue further to reach me via email (hello [at] patdryburgh.com)
Thanks for your patience and understanding.