Did you perchance note whence some of the origins for such "proofs" come? For example, the "first cause" argument, still invoked to day, was (so far as we know) first formulated by a polytheist named Aristotle. While Plato too offered potential fruit for the scholastics, those like Anselm and Aquinas seem to have cared little for Plato and concentrated on adapting Aristotle's proofs.
Also note that "proof" is not used by scientists for the most part but within closed discourse worlds: mathematical spaces with agreed upon axioms and operators, formal languages with agreed upon axioms and/or justifications (modus ponendo ponens, non tertium datur, etc.). Nor is it something we find as any sort of universal but (like writing systems) seems to have a fairly singular history from the Greeks to the Muslims to the scholastics (yes, other cultures developed counting systems and sometimes even some pretty sophisticated algorithms, but like science, mathematics isn't simply the development of some tool but a system).
Basically, these proofs are following not only a tradition that isn't theistic in origin but a systematic and formal thought process which was later transformed into various notational systems and innumerable fields of mathematics. The most famous were around before Jesus, had nothing to do with either Judaism or early Christianity, and didn't get very far until algebra was stolen by the early modern West. And even then, we aren't done. Because not only were the founders of modern science interested in understanding God's works to understand God, they were developing the formal languages necessary to do so (like Liebniz' notation relative to Newton's), and eventually the hope was that the entirety of mathematical science (as it was generally considered to be a science at that time) would be axiomized into a single formal logic. Frege thought he had done this, and was preparing to publish his second work when Bertrand Russell kindly informed him of an error that made the entire system inadequate. Russell, however, received the same (and after far more work; trust me when I say that the three volumes he and Whitehead wrote are densely packed with few explanatory remarks).
Kurt Gödel didn't just show that Russell and Whitehead failed. He proved that the entire hope for an axiomatic mathematics was fruitless. Perhaps the greatest logician of all time, I mention him and this tradition because not only did Gödel offer his own proof of God, but believed that the very thing he had proved to be logically impossible existed for God.
The university system was begun to educate priests, and even in the US most of the older universities (including tiny little places like Harvard) were Christian universities. The connection between universities and religious offices remained for a very long time, and the focus on religious studies remained well beyond the period in which physics and mathematics was mostly about understanding God's works. Is it any wonder that a nearly 2,400 year old tradition that our entire educational system was built upon hasn't quite shed itself of this tendency?