@ starbuck99
Not knowing what article/s you are talking about makes it hard to know the context of the article.
Delete in OS terms you delete a file and it is removed from the File table (so you can't actually see it) in Explorer, but the file remains on your disk and could possibly be recovered using the right software. The space that file takes up is marked as free for use once something else is written to that space traces are removed. But there are forensic tools that can try and recover files even after being overwritten.
So it isn't entirely clear when delete means delete.
When a file is sent to the avast chest, it is encrypted and it is renamed so from outside the chest you can't really identify what is in there, so can't be run, etc. When deleted from the chest, it is still in its encrypted state on the hard disk, but there is no reference to the changed file name in the file table.
Even the data may still be physically on the disk it is encrypted and to all intents and purposes useless to anyone with the tool to recover the file (if they knew its changed name) as they would still have to deal with the encryption.