Well, they are highly specialised. They have shouldered into a very narrow niche in the eco-system. Humans are destroying it.
Applying some kind of social darwinian notion to the situation tends to end up meaning there should only be humans eating rats and cockroaches around, unless the roaches and the rats make a meal out of humanity first.
Kind of boring...
You could as well go after the gorillas. Now there's one evolutionarily useless species managing to carve out virtually bugger all in the form of an ecological niche. Same goes for the chimpanzees and the orangutans, to a somewhat lesser extent.
Or the koalas. A species so specialised on eating eucalyptus leaves, which contains almost nothing one can derive nutrition from, that they spend their lives drugged, and are unable to develop even a neurological system on par with other mammals. Little energy, tiny brains. They're furry, cute, and crudely put together.
Anyway, your logic seems to head in the direction that if a species of animal, or plant for that matter I suppose, turns out to be unable to take whatever humanity happens to throw at it, it should be written off as a "looser", and we can move on to destroying the next species?
The real problem isn't just that species are going extinct. That's more like a symptom. The real problem is that we are turning a world of infinately complex biotopes, where these species made a living, into some kind of monoculture.
Well, rats and roaches it is then, in the end.
