I'm not sure being against DEI stuff is completely off the rails.
"DEI" is an inherent part of the system - being "against DEI" is simply a statement about what kind of "DEI" you actually want.
If a show that mostly featured black people was cancelled due to "looking at where it had successes and wanting a coherent demographic story to sell to advertisers and in an era where synergies between the appeals of shows on the same network was important to driving ratings, working to rearrange its offerings to focus on targeting White audiences," would you so readily dismiss the creator at being miffed at that?
Somewhat later (but still quite a while before what people describe as him “turning”), he would also claim his Dilbert show on UPN was cancelled because he was White, making it the third job he lost for that reason. (More likely, it was cancelled because its audience was both small and White and UPN was, looking at where it had successes and wanting a coherent demographic story to sell to advertisers and in an era where synergies between the appeals of shows on the same network was important to driving ratings, working to rearrange its offerings to focus on targeting Black audiences.)