Some idiot is going on an unnecessary reporting spree. It's mostly pointless reporting the majority of old posts but if someone reports something then some mod will likely handle it. I don't think we should de-facto prohibit people from reporting all old posts but reporting low-quality posts from 5 years ago isn't really needed.
Like I have said several times before, the moderators really need some kind of feedback mechanism to highlight excessive reports coming from or targeting a single user. "Just enforcing the rules" has been a favorite little game of people targeting those who they would rather were not able to speak at all.