When you revise the works of societies of the past, you are destroying the last remnants of their existence. It is a form of erasure. One has to think how this impacts people of the present day. Why should I commit my life and dedication to the work of art if it is to be revisioned and potentially condemned for all eternity? I'd rather die unknown than to have my art become bastardized by future revisionists. This gets to the heart of other matters. Why should one do anything great or noble for their society when there is an interest of future societies to revise who you were and what you did and, again, potentially condemn you for all eternity.
You're right, I think, and it's a little scary that this angle is being downvoted.
Yes, it's erasure. Literally and figuratively. It's harmful.
Yes, it removes incentive to create, and learn, and be challenged. It blurs truth and enables very real horrors of control. It's dangerous.
No creative person wants any of this for their work. It's demoralizing.
Only greedy publishers and rights-holders have pushed for this, and it's entirely out of short-sighted self-interest. The pretense that this is to protect the public is sooo thin.
If you're a parent who feels the need to buy a sanitized Dahl, I have to wonder what you're hoping to accomplish. Sanitized Dahl isn't Dahl, so what's the point?