This is really common and it makes me want to scream.
Dear way too many companies: You don't get a cookie for publicly noting that your industry or sector has problems with hiring and retaining PoC, women, and/or LGBQ and trans folk, and then expect them to volunteer to fix it. Put your damn money where your mouth is.
You want people to spend their own time, away from family, friends, and home, to develop initiatives that will bring better talent into your company, improve employee retention and loyalty, and be great for social perception, and then you want them to be thankful for the opportunity to do so for free? Fuck that. Look, a lot of us do free activism work. And yes, some of us do free private sector activism work. But at its root the resistance to appropriately compensate diversity activists within companies is the message that diversity is, itself, worthless.
So if you want people to help bring value to your company, you need to value the people who are doing so. Make it part of their jobs. Bake it into the structure of your organization.
I see so many places that are willing to spend money on big, visible 'awareness' events, conferences, speakers, ads... and stop at the line of paying the people that organize this work. The message is clear: the value to the company for diversity is advertising.
Now, I'm not accusing these places of being totally evil, like this is some giant, conscious plan. I don't even think they often know that they're doing this. Social awareness on both an individual and institutional level tends to default towards the visible rather than the introspective - for example, many white folks (of which I am one, of course) are very concerned with not being seen as racist, rather than working on internal racism (hence the tendency towards weird defensive anger when one of us gets called-in on something).
So I'm totally willing to believe that most companies, when they start these kinds of initiatives, are really truly believing they're addressing the problem. But the work most be addressed on multiple scales, both the social and visible (events) and the individual (compensation). If you say you value your marginalized and minority employees, then for fuck' s sake, actually value them.