Wikipedia Article:
https://en.wikipedia.org/wiki/Missouri_Waltz#References
It indicates the song was first published/printed in 1912 and that the lyrics have been changed from time to time.
An alternative to dropping the use of it as a state song is to simply change the lyrics.
The melody is very recognizable and virtually no one knows the lyrics.
Of course that would not satisfy some folks, but then one can't satisfy all the folks all the time.
Secondly, it