All: someone downvoted many comments in this thread. We are undoing all of those downvotes and applying them instead to the post they were intended to promote. We're also banning the accounts that did it, at least until we get a promise that this will never happen again.
We'll probably also write some code to find any other accounts that have done this.
I'm reluctant to disable downvoting on the "who is hiring" threads, because not all posts to these threads are appropriate, and the community does a good job of handling those.