Then why can't Christians all get on the same page and make the same claims about God? Why are there so many denomination and views by Christians out there?
I can create a theology based on biblical scripture as easy as anyone else. Being able to use Bible passages to support my claims, regardless of whether they agree with your claims, does that give me authority?
The reason for that is because we are finite human individuals with a variety of life experiences, differing levels of intellectual capabilities and presuppositions. The Apostle Paul, in the first century A.D. addressed this:
"For we know in part and we prophesy in part; but when the perfect comes, the partial will be done away. When I was a child, I used to speak like a child, think like a child, reason like a child; when I became a man, I did away with childish things. For now we see in a mirror dimly, but then face to face; now I know in part, but then I will know fully just as I also have been fully known." 1 Corinthians 13:9-12
Through the centuries there have been great men of God who have contributed to the advancement of the Christian understanding of Biblical doctrine and practice. If we are able to see just a little farther it is partly because we stand on the shoulders of giants.
We strive to refer to the Bible as our one, final, objective standard of truth.
Your question: "Then why can't Christians all get on the same page and make the same claims about God? Why are there so many denomination and views by Christians out there? Can be directed back to the Atheist's worldview exponentially
The Atheistic worldview asserts that there are no objective, universal, abstract, immaterial, binding, laws that govern logic. To be consistent within their worldview which argues that there is no God, no "super"natural realm they must embrace that only the natural/physical universe exists and truth claims therefore are, necessarily subjective/relative.
That means that each living individual (nearly 8 billion) is the final authority of their truth claims.
So, you see, you will have a more difficult time of justifying your position as superior which your question assumes.
Nevertheless, since none of us are carbon copies and "on the same page and make the same claims" about everything, we can allow for differences on each side and enter into dialogue to argue our case.