I didn't follow the history of how this happened, so I don't know the thinking behind the ban on pot stores, but they missed an opportunity to tax them and more adequately fund the D.C. public schools:

DC voters in November approved a ballot initiative that allows adults 21 and older to possess up to two ounces of marijuana, grow up to six plants, and gift up to one ounce of pot to other adults 21 and older. The measure, which took effect Thursday, doesn't legalize sales, so anyone who tries to make a profit off marijuana could still get locked up. Smoking in public remains banned.Marijuana remains illegal under federal law. So it will still be prohibited on federal property, such as parks and monuments. It also remains banned in federally subsidized public housing. DC police likely won't enforce these bans, but federal police agencies might.DC is unique, because its marijuana legalization measure doesn't allow pot stores.