As I recall intermarriage was not allowed in California by law until about 1948.
Restrictive covenants were not outlawed until about the late 1950's to early 1960's.
The above are historical facts take it or leave it.
I never stated So Cal was perfect, however in Orange County, as flawed as it was, the “facts” you posted before were not the case. A small number of blacks lived in Fullerton and Santa Ana back into the 1930s. It was considered “common knowledge” that blacks had to leave Brea and Orange by sundown, but no sign so stating was ever posted nor any law so passed.
By the late 50s or early 560s Fullerton High elected a black student body president. It wasn’t nirvana, but it was better in the OC than the leftist snobs on the west side of LA want to admit.