Frequently expressed across the colonial Commonwealth, Canada to Australia, South Africa and elsewhere.

eg Daisy Bates (sometime wife of Breaker Morant) wrote in the state newspaper in regard of Australian Aborigines:

  Aboriginal civil-rights leader, William Harris, wrote an article in response and said bi-racial Aboriginal people could be of value to Australian society. Bates replied, "as to the half-castes, however early they may be taken and trained, with very few exceptions, the only good half-caste is a dead one."

Miscegenation Laws regarding mixing of races remained in force in Bates part of the world until the 1960s, as did others enforcing the separation of mixed children from their families.

It seems less "a solution to racism" and more an excuse to enforce racist ideas aand attitudes.

Pizza delivery hasn't led me to time machines yet :(

unlike David Ricardo my wants are not infinite lol

[1]: https://en.m.wikipedia.org/wiki/Heterosis

Not just a solution to racism, but also a defense against genocide. Forced interracial "marriages", rape, etc were used as a genocidal tool against the natives along with murder. Natives who refused to mix with whites were derogatorily called racists by the white settlers.

Miscegenation was actually supported by natives, blacks, asians, etc in order preserve their cultures/races in a white dominated nation. Racism ( by all sides ) actually preserved diversity in the US for centuries. Otherwise, everyone would be white due to demographic realities of the nation.