Earlier quoted context omitted.
Not an expert on guerilla cyber-warfare, but isn't it the whole point of this sort of poisoning? If enough people do this the cost of those bouncing emails would become prohibitive. That's my speculation. Would be great to know more from someone who knows the domain better.
You don't bounce emails you prebounce them and clean up your list. This is part of any sensible data engineers process.
You serve a variety of email domains that validate as deliverable, then you accept emails and report the sender, which hurts their deliverability.