San Antonio, St. Louis, Orlando, Miami, Atlanta and the Bronx all seem to disagree with you.
Ha! What proof do you have that Miami, Orlando, and Atlanta can support an MLS team? Miami is one of the most fair weather cities, they can't even support a baseball team and the only reason anyone cares about the NBA team is they are winning. Atlanta couldn't even support an NHL team. I don't know if you have ever been to Atlanta but black people and white conservatives don't care about soccer.
some of the best soccer players our country has ever produced are black...
How does that change the fact that the majority of African-Americans don't care about soccer?
The growth of youth soccer programs inside the city limits of Atlanta would indicate otherwise.