[someguyorother]

> If there's an infinite number of civilisations out there, and one of them is so advanced that we are insects to them, why wouldn't they just exterminate us, or use us as food?

We want to exterminate mosquitoes because they're actively detrimental. Nobody's advocating for the extermination of, say, daddy long-legs spiders even though they're everywhere; and nobody would be advocating for the extermination of mosquitoes if they were all located in Antarctica.

So it takes a very precise level of inferiority to be extermination fodder. If you're too unassuming, there's no reason and so it doesn't happen. If you're dangerous enough that you can fight back and hold your own, it doesn't happen either.

That aliens would find us just the right shade of annoying seems... implausible.