The issue is Creative Commons content, if you are legitimately pruning old low value content of yours that is totaly fine. But rage quits where people just want to take their content and go home, withdrawing it from the commons out of anger, is not OK.
You can always get to older content even deleted content through the regular Creative Commons data dumps that the whole Stack network publishes torrents of. You can also, if you sign an NDA, get a more complete data set for research purposes.
That appears to say you have "you could ask, a mod might action it, but if they're opposed you might be able to beg a dev to ..." That is to say, you really don't "have that".
You can always get to older content even deleted content through the regular Creative Commons data dumps that the whole Stack network publishes torrents of. You can also, if you sign an NDA, get a more complete data set for research purposes.