No, my daughter doesn't have to be a Met fan. But she is. Probably the same reason I'm a Met fan: My dad.
But no, i wouldn't hold it against her if she were a Yankee fan.
But if she were Gay, Christian, Republican, or Ugly, she'd be disowned immediately.
"Mr. Martin Tanner, Baritone, of Dayton, Ohio made his Town Hall debut last night. He came well prepared, but unfortunately his presentation was not up to contemporary professional standards. His voice lacks the range of tonal color necessary to make it consistently interesting. Full time consideration of another endeavor might be in order."