The blanket rejection of black and white thinking is itself a form of black and white thinking– black and white thinking about black and white thinking.
And if black and white thinking about black and white thinking is valid then black and white thinking about other things can be valid too.
So we should reject black and white thinking about black and white thinking and adopt a more nuanced approach that acknowledges that sometimes black and white thinking may be valid.
Because the issue of black and white thinking is not always black and white.