Certainly the government does not want you to know the answer to that question. That is why it offers up its own canard: "They hate us because we are free." Yet, a simple examination of other nations which are free demonstrates how thread-bare this explanation is. Canada, Switzerland, Austria, New Zealand: they are all free, and they are all free of "the threat." We are back to "why?"But there are people who asked the question and know the answer, like the Pentagon.
Even the Pentagon knows the painful answer to the question of "why?" "Muslims do not hate ‘our freedom,’ but rather, they hate our policies. The overwhelming majority voice their objection to what they see as our one-sided support in favor of Israel and against Palestinian rights, and the longstanding, even increasing support for what Muslims collectively see as tyrannies, most notably in Egypt, Saudi Arabia, Jordan, Pakistan, and the Gulf states….the dramatic narrative since 9/11has essentially borne out the entire radical Islamist bill of particulars."Yes I know, just more "blame America first". Well maybe we should consider the idea that American policy is at least partly to blame. If we don't do that we can never win and it will indeed become the "never ending war". Of course that's exactly what the Bush administration and the neocons want, never ending war is a good way to maintain never ending power. That's why they don't want us to ask the question "why" or at least make sure we don't get the right answer.