Another thought re grade school in the 50's
Although we had never heard the term, it was in it's "own" way very multicultural....
Classmates from many varied backgrounds,large % of Jewish students (the school was 2 blocks from the Jewish Community Center), then the usual RC, Lutheran, Methodist, AOG, Christian Science, JW and me the only UPC!!
A true melting pot. (Totally White....no African-American here, maybe an American Indian--not sure)
In Jr High there were a few African American students. Remember, this is the North...and it's COLD!!