It's not trolling. The idea that they just bought a house to live in for a couple of years while their daughter finishes school is BS. It means they intend to be at a minimum be part-time DC residents over the next decade or so.
What's wrong with living in DC? It's a nice place.
Washington DC is one of the most segregated cities in the country - both in terms of race and income. It has an affordable housing problem. It has the seventh highest murder rate of any US city and ranks in or near the top ten for violent crime. Residents have limited political rights. Its metro system is poorly designed, poorly managed, and inadequate for a city of DC's size. Beltway traffic is awful. It was built on a swamp and could be among the American cities most affected by rising sea levels and global warming.
With the exception of the restricted voting rights --and even only then, thanks to gerrymandering away the influence of cities in GOP-run states -- every major US city that is a true city and not a suburban sprawlville shares these problems. The dig against the DC Metro is especially unfair -- it is the third longest rail line in North America and is tied with Chicago for ridership.
Oh, and Washington wasn't built on a swamp, either.