He was reacting to allegations by a fellow kernel developer Matthew Garrett, who called him a "rape apologist" over comments that Ts'o had made on a mailing list in February 2011.
Garrett's comments came after the executive director of The Ada Initiative, Valerie Aurora, exhumed Ts'o's comments and commented on them in an article on the organisation's website; she used recent comments on rape made by a US Republican Senate candidate as the lead-in.
When iTWire contacted Ts'o for his take on the comments levelled at him by both Garrett and Aurora, he responded: "I very much regret having entered that particular debate almost two years ago. I'm sure I said something one or more things in a wrong or unwise things back then, and for that I apologise.
Ts'o's comments were made on a mailing list for the 2011 Australian national Linux conference; complaints had been made against one of the keynote speakers, Mark Pesce, for use of sexualised images in his presentation, and the discussion on the mailing list grew out of that. The entire list has now been taken down but Garrett has archived the thread in question here.
In his response to iTWire, Ts'o continued: "That being said, I do have serious reservations about some of the statistics that were thrown around in that particular debate, two years ago. Consider that there is a huge difference between first degree murder and vehicular/involuntary homicide.
"They both result in someone getting killed, and they are both wrong and evil. However, the underlying causes behind first degree murder and vehicular homicide fueled by alcohol are quite different, and strategies for decreasing the number of homicides by attacking the root causes of one might not be useful for addressing the root causes of the other. Nor might the punishment appropriate for one be necessarily appropriate for the other.
"Similarly, the causes behind what US law enforcements agencies term 'forcible rape' are quite different from what happens when both parties get drunk and then engage in what by definition is sex without consent. I don't believe that it is useful to conflate both of these cases into a single term, or worse, have discussions where people arbitrarily switch back and forth between a broader and a more narrow definition of the term when it suits their rhetorical needs.
"Unfortunately, there seem to be some people who have agendas where nuance is not convenient for their goals, and where it is more convenient to demonise people than to have a more nuanced conversation over what is a very complicated issue.
"My mistake was to try to have that discussion in that particular forum, when emotions were running high, and I should have known better and just stayed away from the whole thing. Unfortunately, I fell into this trap."