I should rephrase. I do care that our president has an anti-American past. It personally galls me to the core, in fact. But my primary concern is because his past is resulting in present and future behavior. His anti-American past cannot harm anyone, other than by how it informs his current decisions.
The most troubling aspect of his past in and of itself is the fact that it is being hidden by the very agents entrusted with revealing such things.