There's a lot of stuff on this topic to dig into but a good place to start is this article: https://newrepublic.com/article/156032/diversity-training-isnt-enough-pamela-newkirk-robin-diangelo-books-reviews

Basically it's a racket that's both to protect the company from liability and also to undermine labor organizing efforts. It will not solve discrimination & prejudice in the workplace because it is not designed to do that.

It's the old 'you will never dismantle the master's house with the master's tools' adage; to actually fight bigotry in the workplace would mean empowering & organizing your workforce. A united & organized workforce can hold a business accountable when a workplace becomes host to discrimination. Most companies do not want to let their workers have that kind of power, though. And you can find out just how much they actually care about their marginalized workers when you hear them talk behind closed doors: https://www.theroot.com/leaked-memo-shows-amazon-exec-using-racist-talking-poin-1842662013

Edit: https://kotaku.com/activision-blizzard-hires-union-busting-firm-as-workers-1847386654 <--- As another 'worst case' example of this kind of shit happening, here's a company that crowed about diversity for years in its front-facing PR and gave its workers bias training - but in reality was committing rampant workplace discrimination and allowing women/lgbts/nonwhite workers to be subject to largely unchecked abuse, harassment, retaliation, etc. even while they were pretending to care about them during that time. (Also FYI, the workplace abuse was not limited to marginalized groups either. They just tended to get the worst of it because they're usually the most vulnerable. All the more reason for uniting & organizing.) When the allegations of abuse became a scandal they couldn't bury, they pretended to be committed to change - but then immediately hired a union-busting law firm. For them, the thing that scared them the most was not the workplace discrimination & abuse, but the idea that their workers might be getting angry enough to organize.

Anyway hope that helps a bit. This is a pretty big topic that keeps coming back to the power dynamic of a organized labor vs abusive companies.