There has been very few times in which the Pistons are favored in a game this season. Even though the Wizards have 10 more wins than the Pistons this season, the current iteration of the Washington Wizards is not a better team than the Pistons as they are in the midst of an 8 game road losing streak.
The roster the Wizards started off the season with a hot start has mostly been injured or traded and we are left with a team that will end the season better in the standings than the Pistons, but they have been far worse than the Pistons the last few months.