Many of these negative claims of Disney being this or that actually originate from an infamous over-the-top book called Walt Disney: Hollywood's Dark Prince by Marc Eliot which is considered a joke among academics. It's worth a read for entertainment's sake, though, because some of Eliot's claims are absolutely crazy.

If you want to learn how African Americans and Jews felt about working with Disney, I suggest checking out many of the online interviews with, say, Floyd Norman (a Disney animator from Walt's time who still works closely with Disney and Pixar) who discusses this topic extensively in places such as JimHillMedia.com among others.

If by any chance you want to read something which has an unbiased view of Disney as a person and which actually uses sources properly, I suggest reading Walt Disney: The Triumph of the American Imagination by Neal Gabler which is generally considered to be the most extensive Disney biography to date. Just check all those works he's cited; there are so many sources in the book that he couldn't print them all so he actually has a website with the complete list of sources.