What's the Title of Darwin's Book? Biologic Irony and the Power of "the"

In an exhibit on how the Nazi regime used natural selection and hereditary principles to justify eugenics and carry out very evil deeds, I found it ironic that the exhibit refers to Darwin's book as On the Origin of the Species.  

Misidentifying the as "the species" seems to indicate that the whole book is about human evolution, when in fact Darwin barely mentions humans at all. As a result this copy does harm by contributing to a misunderstanding of what Darwin does. More importantly, once humans become the central point of Darwin's text, then suddenly the core text of evolutionary thinking suddenly looks like he might have been commited to eugenicist principles. The irony is that in an exhibit showing the horrors of eugenics movement, this misrepresentation in fact provides a subtle rationale for eugenics thinking: it makes possible the assumption that at its core, evolutionary thinking is tied to eugenics.

Odd that this exhibit doesn't  accurately represent Darwin, while the Creation Museum does.