Copper golems can take and place items from and into chests even when the mob_griefing game rule is set to false

But if they didn't sort items surely when they're used in redstone sorting systems the systems would break?

Maybe mojang should add a tag you can add to chests with commands to prevent entities from taking or adding items?

My point is this may be intended behaviour

Thank you for your report!
After consideration, the issue is being closed as Working as Intended.

Please note, that mechanics of the game may change between updates.
Things such as graphics, sounds, world creation, biomes, redstone, villagers, and animals may not work the same in current versions.

Full Version History – Snapshot Version History – The official Minecraft feedback site

Quick Links:
📓 Bug Tracker Guidelines – 💬 Community Support – 📧 Mojang Support (Technical Issues) – 📧 Microsoft Support (Account Issues)
📓 Project Summary – ✍️ Feedback and Suggestions – 📖 Game Wiki