I wouldn't report a post that was that old, even if it was the worst shitpost in the world.  If it made it that long without getting deleted, it's probably best just to leave it alone--not to mention that old posts lose their relevance as time goes on.

As far as the conspiracy theory goes, it's certainly possible that someone could be reporting a lot of your posts out of spite.  I would think that a moderator would catch this, especially if the majority of reports are bad--and if that's the case, the result shouldn't end with posts getting nuked.

Have you seen how much time and effort members like cryptohunter (and all of his alts) put into ranting & raving?  If so, it shouldn't surprise you that a member or members would take the time to sift through someone's posts looking for ones to report.  Now I'm not saying that CH is involved in this, but you get my point.  There are a lot of anal retentive, OCD-type members on this forum who spend a lot of time researching things and whatnot.