Reductio ad absurdum. And also a pretty disgusting comment to make.
Reductio ad absurdum is a perfectly valid form of argumentation. If you don't like the conclusion, that's the point.
> By the same token, it also follows that if I break into your house and rape your wife that's just natural selection and the successful passing on of genetics at play.
We as humans adapt as well, by having a legal system, police, security and developed self defence. Don't forget that we are part of the animal kingdom.