Sure, needing to deal with the question at all is a result of a certain set of cosmological and metaphysical assumptions—but it happens to be a problem that a t

Sure, needing to deal with the question at all is a result of a certain set of cosmological and metaphysical assumptions—but it happens to be a problem that a ton of Western philosophers dealt with, over the years, because they were starting from such a set of assumptions, and so did feel a need to address it, so if you're reading (or reading about) Western philosophy—especially before the 20th century—you're gonna see a lot of it. In Leibniz' case, his work on that problem just happens to be probably his second-most-famous work at all, and better-known than most such efforts, even into our era of atheistic modernism (in part because of the Voltaire connection I mentioned—I'm sure Candide is far more widely-read than anything Leibniz wrote)