...so why is the right to live an absolute right? What does it mean for a right to be absolute? (e.g. if someone kills other people to save himself, was he entitled to do so on the basis of his right to live?) Who gets to decide what rights are absolute and what rights aren't? Whose responsibility is it to enforce these absolute rights (and thereby to impose corresponding obligations on other people)?

The logic of "absolute" rights requires an over-simplification that doesn't reflect how rights work in practice.