Trump would not activate them without the courtesy of local consent.
> Are you sure about that? All last summer, we heard stories of Trump suggesting that the National Guard be deployed, and Democrat mayors and governors refusing. <
Yes, I am sure. But remember this article is talking about the DC National Guard. The president - and only the president - has authority over the DC Guard. No one else can call them up, or order them to stand down.
But when it comes to the states, you are right. The governors have considerable authority there. They can act in their own. And as you noted, many Democrat governors refused to use the Guard during the riots.