Q: Why did Buddha not talk about God?
The purpose of life is to attain enlightenment, but people would much rather like to discuss or argue about abstract metaphysics which leaves their egos intact and even may increase their size! Buddha refused to engage in any teaching or discussion on subjects that did not relate to practical spiritual life.
Atheistic people claim that Buddha taught the doctrine of No Self. This is absolutely false. He taught the doctrine of Anatta (Sanskrit: Anatma–See A Brief Sanskrit Glossary), Not Self, meaning that we must learn what is not the Self so we will not mistakenly identify with it and think we have found the Self. No Self is Niratma, while Not Self is Anatma. They are utterly different words.
Quotions from spiritual teachers or authorities often call to mind the maxim: Figures do not lie, but liars figure.