Microsoft is often under the failed assumption that they can force the adoption of some technology simply by forcing Windows users to see it constantly. Examples include pinning the Store or Edge to the taskbar, and another, it appears, was a mandatory entry in the context menu for the unpopular Paint 3D app.
At present, even if you uninstall the Paint 3D app, the Edit with Paint 3D entry will remain in the context menu, and when you click on it, the link will suggest you install the app from the Store.
“This [inability to remove Paint 3D from context menu” should be addressed after upgrading to Build 21332.”
This is good news for those who want to declutter an already overloaded menu. Microsoft will of course stop pre-installing the Paint 3D app in the next big version of Windows.