Diversity in the sense that people from various walks of life provide diverse(!) opinions is a very good thing. Getting stuck in thought bubbles is a very easy mistake to get into.
"Diversity" in the sense that people explicitly of a given race or sex be placed in a given seat to satisfy some "diversity" quota is not a show of diversity, it's just plain old discrimination.
To pursue minority candidates who are qualified, is in no way discrimination. Unless you assume they are less deserving intrinsically, then it's fair to include them in a search.
Why would those candidates be excluded? Because white guys might suffer? That's a bankrupt argument at the core.
Fairness, the the privileged, looks like discrimination every time.
The comment you are replying to is saying that having demographic quotas is bad.
There's an implied disagreement about what is (what companies are actually in practice doing), but I don't see any disagreement about what should be.
The original point of increasing diversity was to improve decision-making by not having basically an opinion bubble where everyone thinks the same way. So, companies tried to have non-traditional hires which would think differently than the existing employees. It only warped to what we know as "diversity" today later.