This is something I've been thinking a lot about recently but I'm still not sure what is right. My rule of thumb has been that I'll kill any bug that is infesting my house or causing a problem to my health. Like I would kill termites or bed bugs if I had those, or like a leech or a tick. But recently I've been getting a lot of flies in my apartment and while they are technically "infesting" the place, they're not doing anything to harm me, just annoy me. Is it wrong to kill them?
Also I would like to say that if I encountered any of these bugs out in nature I would leave them alone and not harm them, this is only in the context of a threat to your sanitation or home
oh i've spent years thinking about this and still don't really know where i stand either. my general attitude is to gravitate toward "never" but like you had said, if I got bedbugs well... they gotta go, ya know. and if i'm being honest i certainly have killed some bugs that didn't need to die - so I suppose for me it comes down to the same sort of harm reduction ethos underlying veganism more broadly, do your best. you can never reduce your harm to zero.
as for the flies, you could try to make one of those traps that's like a cup with a paper covering it that has a hole in the middle and then fill the cup with something that attracts the flies. when there are a bunch in there, cover the cup and take em outside.
Cool beans, I'm glad everyone seems to be broadly on the same page on this. I'll look into doing the whole cup thing to get rid of them