If you wouldn't call it the Oklahoma Thunder, you can't say St Louis FC or New York FC. It just doesn't sound right and is technically a part of their name.
Why does the quiz give me Orioles when I typed in Whitecaps lol? Is there some sort of wrong type-in or what. Same with typing Montreal (it gave me Real Salt Lake aswell)
Couple of things for MLS:
-LAFC should work for Los Angeles FC
-Revs should work for Revolution
Both type-ins are now accepted.
I couldn't replicate the Orioles/Whitecaps one, though.