I understand your points but at the same time it comes with the medium.

It's one thing for you to write a character in a book and then see this character being turned into something you didn't write in, say, a movie adaptation. Even if it's something non-important, it's your character, you know this character in your head as if he/she was a real person. So when you see the character doing a thing or acting a way in the adaptation you might think "wait, this person I know would never do that!".

The degree to which a creator knows a character goes even further than what you might see at first. If it's a series, certain characteristics might only be explored in later iterations even though the "person" the creator knows in their head was always that way.

But in American comics this is expected to happen. The character isn't only of its creator, the creator is only responsible for putting it out there. And decades will pass, and the character will go through many other creators. Many great stories have been told exactly because someone reinvented the character in a way that was never intended by the original creators. Obviously the opposite also happens, not every story that comes out is gonna be good. But with American comics these things will always happen, since it's a medium that relies on multiple colaborations over the time.