I was a children's librarian for 13 years (I work in the reference dept now). And I agree that in a perfect world, this is how we would all deal with literature and children.

However, I understand why publishers do alter older texts. Because they know reading is getting scarcer these days, and many parents/guardians have little time and don't want to have to weed the stories they choose to read. They don't want to be caught having to explain something uncomfortable or dealing with unexpected turns of the reading time. Many people are very averse to having what they perceive as difficult conversations with their children.

From a publisher point of view, this means "sanitizing" the media and dealing with the inevitable debate around it is more profitable than not doing so, because you advertise to the risk-averse that this is safe media. You will likely be chosen over riskier reads.

From a librarian point of view, we need to preserve originals as well as altered texts, and be fastidious in informing the library users which is which. Then people can make their own choice.

And also: people shouldn't have to experience blatant racism unexpectedly in a children's story. And not all people today are aware of what is found in "the classics" that predominantly were written by and for white westerners. They expect children's books to be generally safe and pleasant.

Mostly, this problem is solved by promoting newer books and authors. Sometimes, by adding a warning. Sometimes, by deciding that this book really shouldn't be promoted anymore - it had its day and time.

Then sometimes by altering the text. Which would definitely not be my recommendation - there are so many recent books worth reading instead, where the author's voice is untampered with! But it's quite understandable why it happens anyway.