I agree, I do appreciate conservation, but species have been hinted to extinction or starved to extinction in history so I do not see the difference between that and human expansion wiping out species.
Whilst we shouldn't go out of our way to kill things, I still think we should do things for the good of mankind as a first prioirity and conservation as a second, because that is how every other species works.
Many, many species have come and gone without our influence, yes, and many others have been wiped out by hunting, foresting, pollution, and so on. The trouble, if someone doesn't care about saving them for the sake of saving them, is that focusing on human needs can have unintended side-effects that wind up endangering us. Many people don't realize that once we've finished sterilizing Earth to be perfectly fit for human habitation, we've probably killed ourselves. It's the butterfly effect, wherein one species depends on another. For example, people plant things in their yards based mostly on how they look, but many insects can only feed from or reproduce on specific plants local to their habitats. A butterfly may be able to eat the nectar from a flower, but its caterpillars can't digest the plant's leaves. Birds that ate them may move on or starve, and no longer spread the seeds of a different plant, and so on. We clear a lot of land in our needs for huge amounts of food, but we still need the insects that pollinate crops. There was a big commotion over honeybees dying off; bees not native to this continent, used to pollinate plants also not native to this continent.
"Save the cute animals" is generally a poor way to approach conservation, but it needs to be treated as something that goes hand in hand with our own priorities. Mass extinctions are something that can kill millions of us in the future as easily as bombs.