There is a fundamental assumption among anti-DEI conservatives that there is only one Best Candidate for any job, one who conveniently looks like them. Anyone who look different, then, obviously can't be the Best Candidate, so someone must have "tipped the scales" to get them in.
Diversity is important because it leads to better ideas, particularly in matters of public policy that affect everyone. I think it's perfectly appropriate for a PR team to use, as one of its hiring guidelines, a goal to assemble people from different backgrounds, which will make everything they produce more relatable to the public. But since Conservatives don't see the value in that at all, all they see is "They wanted to hire a black woman to tick a box", not realizing the value that particular candidate's lived experience brings to that team.