Dehumanizing people by comparing them to pests, rodents, insects or other despised animals is a classic strategy in authoritarian thought. If the people we oppose aren't really human than we can despise them freely, then our anger is righteous, then we really are the virtuous ones.
I want to propose to everyone here that calling political opponents or plutocrats by epithets that dehumanize them is not wise. If we do succeed in dehumanizing them we will dehumanize ourselves in some measure also. Consider these (random ones close at hand, no attribution given because this is not aimed at their authors):
Time to out those kockroaches
It's like someone managed to pick up a great big wet rock, and all the maggots and other slimy creatures became visible for all to see.
Fucking pigs.
I'm sure you've seen others.
We don't need a new rule and it would be impossible to implement in any case. This is just a plea to stop and re-read what you write before you post.