The Hadozee is a good example, though. Even if they didn't spot it, as soon as someone did(and someone always will), then leapt into action and changed it. They changed orcs, Vistani and other things as well. I don't see why they wouldn't leap into action against a 3rd party once someone told them about the racism.
I mean, I don't agree that they "leapt into action" "as soon as someone [spotted it]". It'd been discussed at some length for some time and had got to the point where people were generally thinking "I guess WotC doesn't care" (and indeed a lot of people were suggesting they shouldn't care!) before WotC even acknowledged the issue. Once they did, they did a decent job. It helps that it was anti-Black racism, which is on the sort of racism that US corporations are better at at least
recognising (even if they often perpetuate it).
But it's a good example because it's a case of "the squeaky wheel gets the grease". That wheel was squeaking very loudly, and it was a WotC product.
With 3PPs, it's going to be a lot more complicated, because far less people are going to see any given product, and WotC's thing says "blatant racism", which is theoretically a pretty high bar. I'm not even sure the Hadozee would have reached that, though personally I think the minstrelsy stuff did take it there.
And my experience with corporations is that they're somewhat loathe to publicly call others "racists" (for obvious reasons, I hope). So unless a book is staggeringly obviously racism (i.e. "blatant racism"), they're probably not going to do anything about it. If it's just trading in stereotypes or unfortunate implications/language (which is kind of where the Vistani and Orcs were), I'm skeptical that they'll do anything. Maybe that's fine, but I think it means the whole commitment is a bit questionable. Further, it's quite likely more non-US forms of racism will go ignored because it doesn't immediately make sense, and US corporations and frankly American society in general, has an amazing history of not recognising anti-Native American racism. So I'm pretty skeptical about how that's going to actually work out. And I'm not saying it's not hard - it is! But that just means it's less likely to work out!
On the flip side, corporations have an equally long history, especially US ones, of freaking out about anything that people are telling them is "sexual". They freak out way more about that, than anything but the most severe racism or the like. And LGBTQ+ people are the main target of this. A significant minority of US society suggests merely being LGBTQ+ is a "sexual" thing - that's obviously hardly worth discussing it's such a given. Further there are organised groups actively seeking out LGBTQ+ material to criticise on these grounds. So I believe any LGBTQ+ work is going to get a lot of complaints made directly to WotC about it on those grounds. Those complaints may well not appear on social media, which will make it harder for people to say "That's unwarranted", and I think it's highly likely WotC will burn a few LGBTQ+ creators before realizing they're essentially being played. If they even realize that. There's also a lower bar for calling something "sexual" than calling something "racist", at least for corporations. I think that's wrong, but it's how it seems to work.
So hopefully you'll forgive my rather strong skepticism that this commitment is anything but a commitment to protect their brand, and my belief that it's unlikely to be consistent, fair, or well-handled.