Maybe not, but if it turns out a KKK member or Robin Deangelo gave a racist talk, they should apologize for having their employees being "trained" with it. I don't think the conference analogy works fully though. They're optional. These training things are usually mandatory, so they were required to choose something that this insanely racist content was a part of.
No, but when something this egregious is a part of a product you use, they should have cancelled (if it's paid for) and went with another option. Obviously linkedin is most at fault, but anyone that supports it by using it is also at fault. Coca Cola is definitely responsible for making this a part of the options that their employees were required to be "trained" with.
It's very clear that it's at least a part of the options that they make their employees choose from. And that's more than enough for them to be responsible for it. Even the possibility of something this racist being in their "curriculum" is something that should never happen.