That's, again, a straw man argument. The two are hardly the same, such a comparison is ridiculous

I really don't understand why you think so. Let's see once again:

I said:

Can you live without using a bug spray? No. Because the bugs will kill you with whatever diseases they bring in.

To which you said:

there are many parts where people don't have bug spray, and don't die from disease. To claim that all bugs that bug spray is used on, will kill you with disease, is a straw man argument.

To which I said:

not everyone will come to your house and kill you. Why do you put doors, locks and fencing then??

It is a perfect comparison explaining the point that I would use a bug spray so that I MAY NOT die from disease. I never said I WILL die from disease. I MAY die. And that's why I would use a bug spray so that the meager chances of my dying would be eliminated.

And if 20 mice die, to find some new way to save hundreds of lives, then I'd see that as justified.

Fair enough. But what if the need for the 20 mice to die is eliminated? We kill mice everyday in our agricultural fields, don't we? Because they are pests and if we don't kill them we will have no produce and no food. We daily harm many life forms for our survival. But that doesn't mean we continue doing this even when it's NOT needed, even when it doesn't hamper our survival in any way. After all, non humans are not made for us. We are not superior than them and they are not our servants.