I won't dispute that.
But I will say that this sort of Wall St panic often happens after an election in which the Democrats seize the House. I remember it didn't go well after 2006 when Democrats won. Now in 2018, Democrats regain the House, and the Dow plunges.
Yes, technically, the GOP still is in control. But the Dow see the future.
The Dow reflects the anticipated future in the next 6 months.