Aside from the fact that a theme park ride is a less than ideal venue to address complicated and thorny issues like cultural appropriation and weaponization, slavery, white supremacy, shifting oral traditions based on cultural context, etc., your solution also wouldn't work in other ways. Why would it be the job of West African cultural ambassadors who aren't from the US and do not descend from slaves explain the very American problems with Splash Mountain. Even more of a problem, it's not like adding in and explaining the racist context and white supremacy would appease a lot of the people complaining about this change. No theme park ride, even Splash Mountain, is a good platform for engaging with these topics and clearly Disney does not see it as Splash Mountain's role to do so. Disney is in the entertainment business not the educational business, and even if they were in the educational business, it would be absurd to choose a log flume ride as a platform to address these topics.