The airspace in the area is complex, so it's a challenge to provide useful helicopter routes while reducing potential conflict.
My understanding of why (and also why we're cleared _direct_ a lot of times) is that we move a lot slower than planes, and that ends up being dangerous in its own right in a pattern shared with planes!
Different people have different priorities. /s
“An advanced city is not one where the poor own a car, but one where the rich use public transport.” — Enrique Peñalosa (then-mayor of Bogotá), https://www.ted.com/talks/enrique_penalosa_why_buses_represe...
(Sometimes attributed to differently: “A developed country is not a place where the poor have cars. It's where the rich use public transportation.” ― Gustavo Petro)
Which is why it will not close. It's easier for Congress members, senior staff, etc. to use rather than the drive out to Dulles of BWI. It's convenient for powerful people.