After President Biden dropped out of the 2024 campaign and elevated his Vice President, Kamala Harris, as the presumptive Democratic nominee, supporters of Donald Trump started attacking her as a "DEI hire."
For example, during an interview with CNN’s Manu Raju, Republican Rep. Tim Burchett said this: "100 percent, she was a DEI hire." He's not only one pushing this narrative.
When one person calls another a "DEI hire," they mean they are unqualified, unskilled, and hired only because of their race. They say it because they cannot say publicly what they really want to say.