I'm not into trying to prove that God exists in this thread, but saying that many take science like it's the Word of Truth, exactly like Christians take Jesus word like Word of Truth.
You're right that there are people who misunderstand or abuse science. The "Word of Truth" approach you mention, where people invest themselves into some belief and then close themselves off from further evidence or thought, is disastrous. Especially dangerous is the doctrine of "faith," which directly invites (or compels) people to do that very thing.
However, it seems to me that religion requires that sort of "Word of Truth" mindset, or at least encourages it, whereas science is precisely that force fighting against it. When you level the charge against science that, "Well, scientists have been wrong before," you're missing the point. That scientists have been wrong before is exactly how science is supposed to operate. We don't lock ourselves in with one understanding, one "truth," one dogma, but we work continually to better our understanding of the world and ourselves. We show ourselves to have been wrong about things, time and time again, and this is how we manage to do better. It's a slow and imperfect process, perhaps, but it's the best we can manage thus far.
You can contrast this against religion, which routinely claims to discover capital-t Truth -- a universal Truth for all people and all time -- and then fights (often literally) to keep other people from questioning those Truths or arguing against them or considering other possibilities. Religion does not allow for the kinds of corrections science demands. Science admits it when it has gotten something wrong; religion embraces its errors and enshrines them into (again, sometimes literal) law.
So it's not simple as God doesn't exist because science said so.
God doesn't exist in the same way that fairies don't exist, unicorns don't exist, etc. It's not as though scientists have gone out of their way to prove that God doesn't exist, no. ("Proving negatives" has a negative connotation anyways, though I'd say it can be done in a sense -- see Carl Sagan's The Demon-Haunted World and his discussion of "The Dragon in My Garage" for details.)
What science has done instead, from the beginning, is to work out causes for all of the things that "god" was initially evoked to explain. At some point, people thought you would find god if you climbed Mt. Olympus, but eventually people did and they did not find Zeus waiting there. As human knowledge has grown, our ideas about god have been pushed back further and further into what's sometimes described as "god of the gaps," where our present conception of "god" is really just a reflection of our current ignorance. A sorry state for the great spirits which once were held to move the sun across the sky, carry the Earth upon their backs, etc.
So you're right, it's not as simple as "God doesn't exist because science said so." It's more like, we haven't found God in all of our searching/investigating, or any good evidence for any god, so there's no good reason to believe that any god exists. Like fairies and unicorns, if we discover some god tomorrow hiding in a burning bush somewhere, then it might be sensible to believe that it exists (whatever that "god" might actually be), but until then, I'll remain "atheist" to gods and fairies and unicorns and so forth.
Religion is not my racist grandfather, it was the Christian religion that made the Roman Empire stop slavery and it was the state thousands of years after that, after the Church lost almost all of its political influence, that brought back slavery, and scientists did nothing about it.
I recognize that it's a bit of a tangent, but is this really your take on the history? The Christian religion made the Roman Empire stop slavery -- but then the state brought it back after the Church lost influence? It's an... extraordinarily complex topic, I'll grant, so it's hard to say things are simply one way or the other, but this idea of Christianity as some moral or social improvement over pre-Christian Rome is, I think, at least questionable.
Not only complex, but also controversial, and it seems to me that people have been making efforts over the last several decades to redeem the Christian world -- and maybe your opinion is a product of that -- but let's look:
Slavery did not end in the Roman Empire with the advent of Christianity. It's true that Christianity helped raise the status of many slaves (as all believers were considered equals in the eyes of God), and women, and etc., but at the same time, the Bible does not condemn slavery (and can be seen as implicitly supporting the institution) and slavery survived the Christian conversion of Rome.
Economic realities did change over time, so much European slavery was eventually supplanted by the institution of "serfdom," though slavery itself persisted into the modern age. (And while serfdom may be seen as a kind of "improvement" over chattel slavery, it's no great shakes itself.) Christianity did not fight against this development, either, and can be seen as having a hand in it. When Christian political influence was at its peak, we call it the Middle Ages -- and these were no shining light of racial tolerance or social grace. Were they better or worse than Rome or Greece? Better in some aspects, no doubt, and worse in many, many others. But the emergence of Europe from the Middle Ages into the Renaissance and then Enlightenment, and so forth, was not primarily the Church's doing. Rather, the Church fought tooth and nail against many of the reforms that we now take for granted.
Were there relatively enlightened Christians along the way, and did people sometimes do great things in the name of Jesus/God/the Church? Absolutely. History is a complicated topic, and people are, as always, individual. But to act as though Christianity was some sort of general benefactor for the world I think is just an utter distortion, because there were just as many (or more) atrocities also in the name of Jesus/God/the Church. Christianity was certainly no Khaleesi-esque freer of the slaves; that's simply wrong.