The submission being archived doesn't mean the author doesn't have access to it, if still the owner of the submission.
This is record keeping, so that the author can see his past submissions and possibly make corrections and update any problems.
For example, some new information arose from recent data, but the journal doesn't require a new submission.
Instead, the article is updated, to include this new information (maybe from reader comments, etc).
This also helps the author and editor in certain situations. Taking your situation, for example, the author would communicate the editor that he has updated an archived and rejected paper through the Notiy Editor message. Then, as an Editor, you set a new Editorial decision (try "Resubmit for review" or something like that), and return the submission to the Review queue, assign new reviewers (or the same ones) and open a new round of review.
If you don't want the remove author access to archived submisions you have to change the article authors.
What I would do for archived and unpublished articles:
- Add the Editor responsible for it.
- Make sure you keep record of the real author in case you need it (use the abstract, your bio statement field in the submission or supplementary file, that is up to you)
- Remove the author('s) from the submission.
Test this first or any other alternative method to see how it works fo you.