The OED provides this citation for the sense you seem to intend here:
These attempts to normalize despotism display the impotency as well as the malignity of the Executive.
That’s from the The New York Times, from back on January 24th.
Of 1864.
That’s a century and a half ago. It’s the second-oldest citation for their sense 1a, which is:
- a. transitive. To make normal; to bring or return to a normal or standard condition or state.
Collins says that To normalize something is to treat it as normal or acceptable when it is not. They provide this fine example of it:
We must resist all attempts to normalize racism.
Speaking of race, during the struggle against Apartheid in South Africa last century, normalize meant to racially desegregate and remove (racial) bias from something. The OED gives several citations demonstrating such uses, although they also say these Apartheid-related senses have gone out of use down there during this our current century.
Merriam-Webster have “recently” addressed this matter of a very recent shift in focus or meaning in their article The New 'Normalize': Is the meaning of 'normalization' changing?:
It will sometimes happen that a word suddenly appears everywhere. In the wake of the 2016 presidential election, two such words are currently in the ether: the verb normalize and its related noun, normalization.
The OED’s entry for normalization does include the Albert Schäffle use in the 1892 translation of his 1885 Die Aussichtslosigkeit der Sozialdemokratie (“The Impossibility of Democratic Socialism”) which was referenced by M-W. This is that OED citation:
- 1892 A. C. Morant tr. A. E. F. Schäffle Impossib. Soc. Democracy 107
This whole process of normalization.
The M-W article mentions:
The comedian John Oliver devoted a monologue to the suggestion that Americans resist "the normalization of Donald Trump,” and a recent article in The New Yorker titled "What Normalization Means" reflects in-depth on the mechanisms and reasons behind normalization. In these and similar pieces, the meaning is clear; it's also clearly
different from the definition you'll find in our dictionary.
[...]
'Normalization' originally described a return to a state considered normal. Later, it was used to describe the act of making something variable conform to a standard. Recently, we've seen it used to describe a change in what's considered standard. In this new 'normalization', the standards change to make something considered an outlier 'normal'—not the other way around.
This seems to be the sense you’re trying to get at the history of. Collins certainly does include it, and I have the distinct feeling the OEX lexicographers feel they have it covered between those two citations. That’s in keeping with John Lawler’s comments about this being just a particular context for an existing sense.