I grew up in a 1950s Yankee household, hearing the Brooklyn Dodgers always referred to as “the bums.” Then they moved to CA and I never heard or thought of that again till your post. Wasn’t meant as jibe, just a sudden jolt of history.
Okay.
I also grew up in a Yankee household as my father always watched them. After he passed away I slowly grew away from the Yankees and embraced the California teams.
I was told that the METS wear orange and blue to commemorate the two teams that left for California: the orange of the Giants and the blue of the Dodgers.
I don't know if that's a true story or not, but it's nice thought.