Imminent and assured defeat of a destabilizing neighbor makes Kuwaiti investments more valuable. As the risk of investing at home declines, Kuwaiti money is repatriated. Kuwaitis, like every other sensible person in the world, primarily invests in the U.S. So, to repatriate money to their imminently less risky country, they must sell investments in the U.S.
It's the free market folks.
We've got plenty of political axes to grind, including with the Islamist movement in Kuwait. But this is likely just good old fashioned portfolio rebalancing.
They all agreed and the theory has something to do with them pulling out at the bottom of the market (Like in 1990/91) and then getting back in later after it's gone up. They said it make us billions in profits when this happens !