I suppose you could say the same thing about cm2187's comment from a few minutes ago about the history of terrorism.
Personally, one thing I enjoy about HN is the tangents that discussions sometimes take. If there is something I can learn from a comment, I'm not too worried about whether it is strictly on topic.
A tangent to the topic, sure, I love it. But hijacking the discussion to draw attention to something that has absolutely nothing to do with either the topic or relevant to a specific comment it almost the definition of a troll. Despite a glancing similarity to a detail not relevant to the topic, GP was not relevant to the comment he replied to.
Personally, one thing I enjoy about HN is the tangents that discussions sometimes take. If there is something I can learn from a comment, I'm not too worried about whether it is strictly on topic.