One problem with the current anti-spam environment
One of the problems with the current anti-spam environment is that there are not enough disincentives against doing really horrible things, like spam, virus, and so on notification autoresponders, or challenge response systems, or your favorite abuse. Practically speaking, people doing these things do not bear any costs for their actions, or at least none large enough to make them notice anything wrong.
(In fact there pretty much aren't any disincentives at the moment. There are a few blocklists of places that do bad things, but I doubt they're very widely used.)
In the absence of any visible costs to you, or at least to your institution, many of these things look very attractive. (And when they are being driven by higher powers, the lack of consequences makes it harder to argue against them.)
Unfortunately it is difficult to see how to turn around this situation. I think that the only effective disincentive that people will notice is for their real email to start not getting through, but the problem with such punitive blocks is that users get upset when you block email that they genuinely want. Almost by definition the only useful places to apply punitive blocks are the places receiving a lot of real email from the misbehaving sources, which means a lot of displeased users.
This is in a sense a tragedy of the commons issue, much like the rest of the email situation. (And I don't think that explaining it to people will really help; most people are to some degree fundamentally selfish, so we are bad at enduring pain for the benefit of random strangers or some indistinct higher goal.)