So, it's somehow a bad thing that these people were stopped?
Jet fuel will burn. It's not like gasoline, either, more like kerosene. Rupturing a line under pressure will guarantee a spray of fine droplets, which will readily burn. That's the principle of the burner in a boiler. As pressure drops, it will also begin to burn in the pipes, as oxygen allows. The burning liquid will flow, finding cracks and fissures that will allow it to continue to move, and will spread fire as it goes. It, and the heavy, toxic, smoke it produces would fill spaces, asphyxiating anyone unable to flee. The results in a crowded area would be pretty horrifying. Low-tech, but deadly.
There are people here who expect to find someone to blame for everything perpetrated on America, unless you blame the perpetrators. If it isn't a present or past politician, it just doesn't appear on their event horizon.
The fact that, somehow, they haven't been personally contacted to direct every facet of our government, is reason enough for them to blather on about opportunities missed, and decisions that failed, in their minds, to produce the effects that they wished for.
There are no sides available in this struggle. If you're American, the Islamic Fundamentalists want you dead.