I'd agree on the public shaming point - something like Glassdoor that could be anonymous?
You can also privately shame these behaviours by directly reaching out to hiring managers at the companies they're recruiting into and informing them it's damaging to their reputation. I've done this after being hired - told the new company that they should switch recruiters due to bad practice.
Yeah, I mean ultimately it's basically just Yelp for recruiters. I know people get mad about public shaming, but I think that a Yelp-esque site is useful in any competitive industry - shaming the bad ones means that the good ones get more business, which is good.
It's a shame because recruitment is another high pressure sales-like environment where targets and commission are king. Especially early career, taking shortcuts can seem the only way to keep up. The tech industry (in the UK at least) talks - a lot - and word gets around quick leading these behaviours to have a damaging, lasting impact.
I've worked with enough salespeople and recruiters to be sympathetic to the pressure put on them. There are a lot of behaviors that salespeople engage in, like selling futures and other questionable things, that I don't like, but I can understand based on the position that they're put in.
But ghosting stands out as particular egregious because it's so, so, so easy to not do. We're talking seconds of effort to send a templated email. However high-pressure their environment may be, it doesn't excuse ghosting.
You can also privately shame these behaviours by directly reaching out to hiring managers at the companies they're recruiting into and informing them it's damaging to their reputation. I've done this after being hired - told the new company that they should switch recruiters due to bad practice.