Many creationists have the misconception that skeptics and atheists who accept the theory of evolution have the notion that evolution and natural selection are good things, and something to embrace and to root for. This is very often related to the concept that evolution is "natural" and the way that "nature" works (and therefore a good and desirable thing.) Therefore if something is (seemingly) against evolution and natural selection, it's therefore "unnatural" and undesirable.
Some creationists use this notion to attack atheism and "evolutionism" (as they call it.) Others use it to argue against some other things they oppose, such as homosexuality (they argue that homosexuality is "unnatural" and against the concept of evolution and natural selection.)
Unfortunately, even some atheists have this misconception. (There are even a few atheists who argue against homosexuality using this very argument.)
This is all wrong, and a huge misunderstanding of what evolution and natural selection are. They are not "good" or "bad", they just happen. They do not have a mind or a goal, they do not aim for anything, nor are they inherently desirable and good. As said, they just are, period. It's a completely mindless, aimless natural phenomenon that just happens, period. They don't care if something they affect is for "good" or "bad" (because "they" are nothing more than simple blind natural laws in action.)
Natural selection is not automatically "good" or desirable. Sometimes it might be, sometimes it's not. Much of human history has actually been a fight to surpass and overthrow natural selection, and that has been for the better. Most prominently, natural selection would mean that many diseases would have killed a good majority of people, but human medicine has overcome that problem.
(Although, one could argue that even our progress in medicine has been a kind of "natural selection" because it has succeeded in helping our species survive, which is the essence of evolution. But as said, there's no "right" or "wrong" natural selection. The most one could say is that natural selection has "failed" in a sense when a species goes extinct.)
Even if something that the human species does to better the lives of its individuals (eg. through advances in medicine) were to be considered "against natural selection" and "unnatural" (which is just a silly idea, but let's play with that thought for a moment for the sake of argument) then so what? Who exactly cares? As said, evolution and natural selection are mindless physical processes, and there's nothing in them that ought to be respected or followed. If something about evolution and natural selection is bad for us, then there's absolutely no reason to just submit to it. There's nothing wrong in "fighting back" (so to speak.)
(Of course the whole concept of something being "unnatural" is completely nonsensical. "Nature" has no goals or rules that should be followed. Nature just is, nothing more. We can't be "unnatural" even if we wanted to because we are part of this physical universe. We are bound to the properties and laws of the universe, so the whole concept of something being "unnatural" is just silly and makes no sense.)