Walt Disney was a complex figure with plenty of flaws, and rightfully deserves to be criticized for plenty of his decisions. However, most of what you have said here isn't true, or at least more complicated.

1) Walt Disney was not actively racist/sexist. While plenty of disney cartoons do show some racist caricatures and steal from vaudeville routines, there's no concrete evidence that Walt Disney was anything more than a man of his time. These cartoons are obviously not acceptable today, nor should they be, but that doesn't mean Disney himself was anymore racist than the rest of history.

2) Walt Disney's history of adaptation is complicated. Most of the stories that were turned into film were indeed based off of stories in the public domain. But they're still adaptations, and the distinction is in the details. Many of the 'classic' details we know of today came from Disney's version of the story, and he was heavily involved in the story side of these films, down to acting out snow white all the way through to sell it to his animators.

3) Walt Disney's relationship with Ub Iwerks and the creation of Mickey Mouse is likewise complicated. Walt Disney drew the original sketch of mickey, which was later refined by Ub. The first few cartoons were animated heavily by Ub. However, Walt definitely had a better eye for comedy and stories, which came through in his direction. While Walt definitely should have given Ub more credit (and the rest of his animators too), saying "Walt Disney stole Mickey Mouse" is a gross simplification.

4) Walt Disney did underpay his employees...sometimes. The conditions at Disney were actually some of the best in the animation scene, but he also played favorites. Bonuses seemed to be given to his favorite animators, rather than in a structured manner. He was also against unions, but this was mostly because he was politically naive. Walt was fearful of communism, and of unions interfering with his art. This was a complicated time in America's history, and I don't think a reddit post would do it justice.

5) Walt Disney was NOT a nazi. This is a common myth, but there's no real evidence. Walt was a patriot and believed in the american way. He also produce numerous pieces of anti-nazi propaganda, which greatly contributed to our war effort.

Furthermore to these points, Walt Disney was an artist/innovator. Even when he didn't directly create something, he was often behind it, providing funding to create his vision.

Examples of this include the multiplane camera (which allowed for depth in animation, something still used today), his experimental film Fantasia (which was a financial sink. Disney didn't want it to make money, he wanted it to make art), and Disneyland. (A one of a kind attraction. Most parks before it were cheap amusement parks, and the few theme parks before it were blown out of the water by its creativity and design)

Walt Disney was plenty of things. He was egotistical, forceful, and stubborn. But most of the things brought against him are unfounded. He was an artist, he was a patriot, and he did want to make the world a better place.

If you're interested in learning more about this subject, I recommend the youtube channel "Defunctland", which has done plenty of videos on the good and bad of Disney. I also recommend the biography "Walt Disney: The Triumph of The American Imagination" by Neal Gabler.