So I just tried it. Uploaded 200 MB file through web. Checked that my MacBook shows the .icloud file. Moved whole folder with it. Was gone from the iCloud web BUT my laptop kept downloading it. Also it is in the Settings > Data & Security.
I think this is a sync issue. What happens when the files are still uploading on one device, while being donwloaded on another. Will the files waiting to uploaded disappear?
1) Other devices don't see the files that are still being uploaded
2) Tried creating a folder, uploading 200 MB file in it and moving the folder to to local drive. Works as expected. After upload finished, the folder reappeared with the file in it.
So, the files waiting to be uploaded won't disappear.
I think you are interpreting it wrong. The article is talking about all your files are already in iCloud Drive, and then you get a new Mac and move stuff around.
Perhaps the author is experiencing a bug and you are not. Your inability to replicate the bug does not prove it doesn't exist. Though many helpdesks would take your side.
So. What is the fuzz?