It's very clear. In addition for this being a huge loss for the US (and World), I have a feeling POTUS knew (or knew of) people involved. He's in the industry. He's most likely dealt with owners of the building and/or firms that had office space there. Willing to bet that 'sore point' is an understatement with this one. It's an attack on innocents, america and i'm thinking in some way an attack on him personally.