Ad odium

The association fallacy is a formal logical fallacy that asserts that properties of one thing must also be properties of another thing, if both things belong to the same group. For example, a fallacious arguer may claim that "bears are animals, and bears are dangerous; therefore your dog, which is also an animal, must be dangerous."

Spitefulness is a negative emotion that can be based on the needs for control and status. Sometimes it is unfounded and stems from bullying. At other times, it comes from a need for justice and revenge.

To act in negative ways towards other, people tell themselves stories that justify their actions, typically saying 'they deserve it'. An appeal to spite supports this story and so creates a bond with the other person which leads them to accept the fallacious argument.

There is a universal delight in the discomfort of others. Germans have a word for this: schadenfreude. There is hence humor in seeing others slip on a banana skin. There is additional delight in seeing those who put themselves above you taking a fall.

Ad odium is a special case of Appeal to emotion.