The question is why they're spending real effort on blocking archivists. All they had to do was keep doing nothing for a few days. The cost to them might have been a couple hundred dollars' worth of bandwidth, at most, which I think archivists would have been happy to pay--they've done more before. (That's estimating based on small-scale commercial hosting prices; it might not even register on whatever enterprise uplink Yahoo/Verizon uses.)
Instead they've got at least one professional taking time away from productive work to fuck with archivists at no benefit to anyone. It's possible that the wage-hours spent on this actually exceed what the bandwidth costs would have been. It's astonishingly petty.
Is it possible that there may be some kind of political angle to all of this; that archiving this information for the future might allow someone to find out something that someone else doesn't want to come to light?
</conspiracy tinfoil hat>