Thinking that you can search for truth while ignoring how most of the world thinks about and addresses these issues is like thinking you can study urban planning without traveling to other towns. While there are some schools of thought that take such a tightly analytic view of philosophy those represent only a single strain of philosophy, and a highly Western continental one at that.
It is worth mentioning that Descarte thought he was doing just this kind of rational searching free of all philosophical conceptions but, for him, the proof of God's existence was obvious as a rational axiom using the same methods as his cogito. I think most of us in the more secular setting of hacker news would consider that portion of his rationalism to be the product of his cultural background.
Just as travel expands your understanding of where you are from, engaging with many traditions of thought is one of the only ways to actually become aware of the assumptions and biases inherent in your own.