Marcus Porcius Cato wrote:
could this be because Armus has killed Tasha?
I don't think so. For one thing, Data doesn't say that's why, and you would think he might, no? Neither does Data appear to petition for Fajo to receive the death penalty, even though he killed Varria.
Basically I don't see any evidence that Data's reasoning is punitive, or that he subscribes to a retributive theory of justice at all.