The only answer is because urbanists just like some things and hate others, and we should create laws and act according to their feelings.
That's probably right, they hate parking lots in downtown areas so they advocate that land value should be a flat tax without taxing improvements (buildings) on the land. But that would only drive the most profit-driven uses for land. So no mixed-use unless it's profitable, apartments must be priced as high as possible, and so on. The problem is that this basically creates dead zones that get landbanked and can never be used for anything or by anyone unless they're super-rich, or gets bounced around in auction.
Note how all the existing lines are mostly a parabola or, well, line shape. What he created was a multi branched root system, the scale of which has no precedent in DC. It’s just complete fantasy.
Despite drawing not one, but two lines, I was willing to give him the benefit of the doubt that "maybe he means that the split teal line is 'alternative 1' and 'alternative 2' like real plans are", but no, he wants all of them. So instead of "just one (more) line (bro)" it's actually closer to 5.
I would assume that the Washington METRO users actually
like their system (even now, it's probably nicer than New York's subway) and that it is just the "Orange Line" instead of the "H Line" (or whatever), and by "H Line" they mean "H Line with the circle around it, not the triangle because the triangle means you skip half the stops and end up in Stabbytown and only a fool would mistake the H Line Express for the H Line", plus the whole thing was a compromise for freeways. Pretty sure that
@quaawaa pointed out once that the system was always designed for commuters and (to a lesser extent) tourists, not the rest of the city, which is rather crummy even by big city standards.
The teal line is basically a completely redundant version of the blue line east of the Beltway (on the west side it's a redundant version of the orange line) but instead of going to anywhere useful, goes straight into the ghetto. Due to the usual arrogance of the urbanists I doubt that he'd even accept being told that such a line is not exactly to be a game-changer.