I wouldn’t circumscribe the issue you rise just to "junk accounts". If I’m reading your point correctly, you are vouching for a purge of that sort of accounts, that have been inactive for quite some time, in case they were to spring back to like after being sold, with some meaningful associated rank and possibly some available sMerits.

If there is a risk that those junk accounts may be sold, the same goes for any longstanding inactive account (or otherwise). The fact that the content is basically social reports, does not add more risk to them being sold than any other account. Account sales is not prohibited, and although I do not like people being able to take such shortcuts, it remains an open front which is both doable and potentially non-uniformly pursued (tagged).

Making content specific decisions for accounts with posts that are not against the rules (but social report related) seems pretty harsh, and would give more ammunition to haters (and rightly so in this case).

By purge I guess you mean deletion, but since accounts are not deleted, the next closest would be a lockdown of some kind of these accounts. Nevertheless, people should be entitled to come back to their accounts after a period of inactivity if they wish.