Intentionally or not, you've just written something very profound that should always be at the forefront of these arguments.
Evolution can only teach by what physical process -- HOW -- we got here. It is science and only science, and therefore only answers the less important half of the big question. The other half, which evolution can't even touch, is WHY are we here, what purpose do we have. This is the job of religion.
Unfortunately, Creation Science tries to cross the line and also explain how, and does a quite pitiful job of it. Religion's useful place in explaining the physical world went away a long time ago, when we realized lightning and storms were not God's wrath, and that rain was not coming down through openings in the firmament.
First, to state the obvious, evolution can't teach, only teachers can. One can exaggerate the evolutionary biologist's capacity to tell us "HOW" we got here. Are histories of human immigration--in many ways a physical process--within the competence of evolutionary theory? And if one only means that it can tell us how we inherited our particular genes, I suspect we are mistaking the theoretical construct for observation. (The observable science, of course, being the field of genetics.) But to ignore that point, it seems historical geneaology has far surer methods of proof than related attempts at extending its fields back into prehistorical times.
In comprehending how an endeavour like natural history proceeds, my greatest difficulty came not from reading scientific-sounding idiots like Dawkins, or his highly creative opponents, but rather from my own thought experiment:
Pretend a massive event like World War II extended over a million years.
Now reconstruct it using the physical evidence.
Oh, and there are no written records whatsoever. Have a nice day.
The task is staggering, and I suspect it would take another million years to recreate even an approximation of it. Not that nobody should try such a reconstruction, but it seems that both the sheer quantity of required information, and the presence of insurmountable information gaps--"knowledge bottlenecks" if you will--precludes natural history, and thus evolutionary theory, from being anything other than a highly, highly speculative endeavor.