Thank you, @calathea!
they probably don't even think about what consequences their actions have
In my opinion it should be pretty obvious that using poison designed for animals can have negative effects for the nearby wildlife. It's not exactly that difficult to imagine that the poisoned rats gets eaten by owls and other predators. I don't think it's good enough for them to pretend that they are ignorant; it seems more likely that they just don't care.
However, you make a good point, I'm just not sure I agree fully with it. But you're completely right that this happens a lot. Like when someone throws away a cigarette stump; no one expects them to end up in the ocean where the leftover nicotine can affect the hormones of fish, and the filter get stuck inside the guts.
I think they may think in terms of short term gain, killing the rodents that they see as a pest for their crops. I don't think they stop to think about what effects this poison has on the wider ecosystem.
Ah, I see what you mean.
Ironically they will most likely end up with a lot more rats if it ends up killing all the animals in the area that prey on rats.