So what's the difference between using noreply, and using somnething like replybot and ... just ignoring those e-mails 99% of the time?

The implication of what the change in the "from" affordance meant to the user.

When we switched from "no-reply" to an actual address (help@artistdomain.com), and we couldn't respond, people got angry.

What is 'faster horse' syndrome, out of interest? Never heard that but it sounds good.

Given the ability to suggest things, users will always demand a faster horse, more sleep, more sex and to lose weight.

Basically its saying, don't solicit opinions because it all normalizes to "I want things to be better"