You are incorrect. The attempt to take Washington in 1864 was a strategic attempt to force the union army to divide in two, thus relieving pressure on Richmond. It sought no more to bring Washington into the confederacy than the Gettysburg campaign did with Pennsylvania.
In the case of that expedition, Washington was saved quite literally by a day. Early's army was delayed by a single day's time at the Monocacy River in Maryland. They easily overcome an inferior union force put there to delay their advance, but the loss of a day's time allowed Fort Stevens in D.C. to be reinforced from what would have otherwise been an easy capture.
Gianni is referring to, of course, the decisions of the confederates NOT to pursue the union forces into Washington after the battle of Manassas. In mid 1861 the confederate armies held a line within spitting distance of the city. Jefferson Davis was conducting confederate war operations for a time from Fairfax Courthouse, just 15 miles to the west of the capital. Yet they decided not to pursue, hoping incorrectly that the two sides could still part their separate ways without attempting to conquer each other.
I am very well aware of what Gianni was referring to.
The fact is both forces were exhausted by the battle.
The South did not stop from taking Washington at out of some sense of goodness of its heart.
If they never intended to attack Washington that was their mistake.
They attacked the North twice and were beaten back twice.
What hat size do you wear anyway?