Lice have no choice in their lot in the universe. Do you think if they had intelligence the ability to choose their lot that they would choose their current one again? I doubt it personally. You can detest their mode of existence whilst still having empathy for them I think
Why would you have empathy for something that is literally incapable of things like empathy. Or any kind of emotion or thought. This is ridiculous guys, you might as well have empathy for a rock.
Counterexample: Humans are lice to the ecosystem of Earth, and we choose to be that way.