There's only so much moderation a single person can handle in a day. The NY Times moderation team posted some stats a ways back, it worked out to about 800 items/person/day. Which, in an 8-hour day works out to an item every 35 seconds. Sustained. Throughout the entire day.
Techs can leverage patterns, even if it means a lot of ad hoc code.
Building training systems is even better.
Considering what Reddit's been through in the past couple of years by way of direct information attacks (even not counting any systems-level attacks), involving coloured tablets and giant orange peaches, I don't find the story that dev time has been accounted for particularly unreasonable.
1. I agree that it shouldn't, but they did so. Updated post with link. In another post, he emphasized the "war" part much more, but I think he deleted it. It was fairly angry.
2. I'm having trouble finding their burn rate; the linked article at least hints that they'll use this money to attract talent.
2. They've had plenty of money from investments though, their dev team is reasonably sized.
3. This one seems pretty accurate.