What we fail to grasp is the depth of their committment, which stands in stark contrast to our inability to commit, unless it's relatively painless. If we understood their committment to our utter eradication via any available means, we'd be much closer to actually waging an effective war on terror.
British officials are still careful to avoid any mention of Islam while commenting upon these homegrown terrorists. Fact that it's the enemy's prime motivation can never be uttered.
I think people understand Islamic committment. They just don't want to contemplate what the only solution might end up being.