It all started when @A_Libellule and I got into a Twitter discussion about this particular issue. In the course of the discussion I had a realization about my core moral position here:

If a group has to choose between living as slaves or committing genocide, picking the latter is morally legitimate.

It would certainly be nice if the queerrats (and interested Cantus humans) could find some solution short of genocide (genocide is ugly and invites counter-genocides and so on), but they are not obliged to do so and they are not obliged to remain slaves instead of committing genocide. The Cantus humans lost all moral standing to complain about it the moment that they started keeping queerrats as slaves (and, lest we forget, wiping out entire queerrat colonies when they felt like it), just as if you try to keep someone as a slave you lose the grounds to complain if they kill you to regain their freedom.

By the way all of this applies if a group is choosing between living as slaves or 'merely' killing some (significant) number of the people keeping them as slaves. I am just taking it all the way to genocide as an extreme case.

(Naturally this deeply colours my view of Squealer's rebellion and his fate and also my overall views on the Cantus humans.)

I could go on at greater length here but I suspect that this is the kind of thing where either you agree immediately or where you are not going to be convinced at all.

Note that you can make a functional argument over whether the queerrats were going to commit genocide or simply kill some number of humans and then stop. My personal view is that they were going to have to go all the way to genocide and they knew it; one surviving breeding pair of Cantus humans was potentially all that was necessary to take over the world again and destroy all queerrats, so none could really be allowed to survive.