They'll get there eventually. If their network sucks in a small town while they're still testing things out it's less visible than if their coverage sucks in the capitol.
Actually, Ellicott City is between Baltimore and Washington, DC. So many people who work in the nation's capital could live or also commute from there. I actually know several people who do this, so might as well put the LTE in the capital.
Ellicott City is part of the Baltimore DC area, but it is not between the two. It's to the west of Baltimore, and about 20 miles from DC.As you drive down I-95 towards DC (at 3 MPH in rush hour) you quickly loose LTE. By Laurel it's difficult to get solid 3G.--less talk, more music