Incomprehensible Truthers

There's something I'll never understand about the Truthers' fascination with WTC7. Rosie, in addition to her groundbreaking scientific discovery about steel being impervious to fire, also stated that while planes did fly into WTC1 and 2, WTC7 was brought down by explosives. What are we supposed to believe about this? That the government somehow managed to have planes flown into the Twin Towers, but figured their evil plan just wouldn't be complete if they couldn't bring down that much smaller building that no one outside of the New York area even knew existed? I guess this is why Truthers flood the zone with details of little relevance. Their big picture just makes no sense.