In that case the word arguably can't be applied to people either, as Eliezer pointed out in this post.

Yes, it can. People really are malicious sometimes. That we are biased to attribute malice to enemies even when none is present does not rule out malice existing in people.

The only time people actively "desire to harm another" is when (they believe that) they are punishing the other according to what we would call TDT/UDT.

That just isn't true. And even if it were the fact that a TDT or UDT agent may do a similar action does not mean that a person is not feeling malice.

Of course, the same motive applies to an AI even one whose terminal goals are indifferent to humans.

Yes, not that they would need to apply that reasoning with humans. You don't need to punish people when you can just consume them as resources.