The rule is - older than 90 days w/o a post, it's too old to reactivate. Mods have leeway within their own districts which is why you sometimes see a difference in enforcement.
I often let a thread be reactivated in one of my low-traffic forums just to get the traffic. D&T is anything but low-traffic, however. Still, I don't enforce it strictly here either but, as in the "green dot" thread - well, that was just egregious.
There has been enough comment on this thread that since it is so old, and since the thread has been hijacked so often and since so many have groaned about it - the kinder and gentler mod has put up a poll.