If only artists could hold copyrights to their works, this wouldn’t be an issue.
Corporations are usually not the ones who create art, they just hire people who do. If Disney spends an astronomical amount on money on hiring artists and producing a work, there should be a separate set of laws that protects them from someone sweeping in and stealing the franchise or the product. It shouldn’t be down to copyright-laws, because Disney isn’t an artist.
Copyright also grants the right to opt out of the commercialization of your work. Even if you really like a painting I have done, you should not have the right to demand that I or someone else sell prints of it. If I instead want to just keep it on my Instagram profile, in my attic or hanging on the walls of a gallery, I should be free to do so.
If you make something public people have the right to look at it and to get inspired by it, but I don’t think it’s unfair to ask that the artist retains the commercial rights to it.
I think you could argue that this is an example of cognitive dissonance. It is uncomfortable to come face to face with new information that contradicts your beliefs or actions, and it requires energy if you want to integrate that new information into your worldview and adjust your actions. It is much easier to deny that information, even when it is clearly true.
For example, when it came out that aspartame might cause cancer, if you (like me) have eaten/drunk a lot of products containing it or have had a strong belief that it was completely safe, then it may be more comfortable for you to criticize WHO or think “well, it’s not really relevant for me because my family isn’t predisposed for cancer.” If you didn’t care about aspartame or artificial sweeteners before, you will probably readily accept that there may or may not be a cancer link.