Now, let's take a step back to define our terms before we move forward:
Biological Micro-Evolution: Random mutation (Such as a gene mutating to produce a larger beak size in a bird species) and natural selection (Such as the birds with the larger beaks having more access to food and thus, not starving to death as often) producing observable changes in a species.
Biological Macro-Evolution: The extrapolation of observed evolutionary mechanisms (natural selection and random mutation) to unobserved levels. That is, assuming that because we observe minor adjustment of species via natural selection and random mutation and given enough time (the billions of years recorded in the fossil record) these processes can generate all the diversity of life from plants, animals, and microbes.
The atheists I have spoken to would argue that there is no reason to assume a limit on evolution's abilities and that the simplest explanation, via Occam's Razor, is that there is no limit.
However, this is where the theistic and atheistic worldviews clash. If you already accept the existence of God, and have a book from him that tells you how he created the world, the simplest explanation will be different.
But for the sake of argument, let's try on an atheistic worldview. Even from this point of view, biological macro-evolution is not a fact. It is an assumption about unobserved (directly or indirectly) ancient events based on directly observed modern events. So why are Christians viewed as heretics when they reject the view that all life shares a common ancestor? With some colleges even refusing to allow creationists to speak!
Naturalists are scared. They know either subconsciously or consciously that they have no other explanation for the diversity of life. Their worldview would be shattered and crushed without macro-evolution. So they lash out against anyone who opposes it. They push it as an undeniable fact. Those who deny that modern humans are descended from apes are regarded on the same level as those who believe the earth is flat.
Yet nobody bats an eye when someone claims that Jesus didn't exist despite the vast majority of historians disagreeing. It seems we don't have a religiously tolerant culture at all. We have a culture that preaches tolerance to every religion except conservative Abrahamic religions. Even Conservative Islam seems to receive far more sympathy than Conservative Christianity.
When people say "I have no problem with Christians", what they normally mean is "I have no problem with liberal Christians who accept macro-evolution/common descent and don't hold to any major biblical values". Maybe this is what the bible means when it says Satan deceives the nations.