I'm a bit confused about what is being discussed here. Does anyone actually argue that calling it a terrorist attack is somehow mistaken or prejudicial?
Two answers.
First, I argue that it may be prejudicial.
I argue that an attack on the Pentagon isn't prima facie terrorism. I argue that an attack on the Pentagon, in some situations, could be a fairly straightforward act of war, where Al Qa'ida (or whoever), believing that the Pentagon is directing military operations against them, makes a decision to retialiate in an effort to put a stop to this.
Now, I /also/ argue that this was not the case in this situation. The biggest evidence is the NYC attack, which /is/ prima facie terrorism; but also, I don't see what military purpose Al Qa'ida could have accomplished. It's not as if the Pentagon was directing anything big at them -- they were investigating the Cole attack, but anything else was covert (assuming that anything else even existed), and pales in comparison with the huge and very overt war that the Pentagon waged /afterwards/. If nothing else, the attack was a gross miscalculation -- but it seems much more likely to me that the purpose was to terrorise, and not to achieve any particular military goal at all. So it was terrorism.
But that fact is not obvious until you think about it. And if Al Qa'ida is trying to claim that the attack /was/ military, then it even becomes POV to /claim/ that fact (even though I agree).
But the second answer is that this is mostly irrelevant. If some Al Qa'ida supporter is still maintaining that the attacks were not terrorism (which I doubt, actually), then the article /body/ is the place to explain this in an NPOV fashion. If the attacks were commonly referred to as "the September 11 terrorism", then [[September 11 terrorism]] would still be a good article /title/ -- and the body could say if that name was disputed.
But that's not how they're referred to. Most often, I hear just "9/11", but that's ambiguous, so [[9/11]] and even [[September 11]] are bad titles. Among disambuated names, "the September 11 attack" /is/ more common. Now if there was some /other/ September 11 attack called just that (I don't think so -- the Chilean coup is called "coup", not "attack"), then we need to decide whether "2001" or "terrorist" disambiguates better. Generally, I would prefer a year as a policy (or convention, rather), since they almost always work when they apply -- a good convention.
Moral: Short titles, as long as they aren't ambiguous, are generally better. Not so much because a longer title runs the risk introducing a POV term (indeed, a longer /article/ is almost always /less/ POV!), but because a shorter phrase will almost always be more common. That is how human language works.
-- Toby