"Science" doesn't make any such assumption, although individual scientists may.
Personally, I reject the "all men are flawed" and "only redemption is by faith" parts of your statement. Primarily, flaws are subjective. Anything that you can consider a "flaw" in a normal, healthy human being I believe I can point to as a situation-specific survival trait. Unless, of course, you're talking about physical flaws or limitations, which is either an error in design or the result of evolution (depending on your viewpoint), and not necessarily a flaw of the person him/herself.
Furthermore, you will need to define what you mean by "redemption". As in redemption from what or for what? And you will also need to provide your proof that this redemption actually happens, if you want me to believe your book (which I am assuming is the Bible) is "100% accurate". As far as I can recall, there is no evidence of any actual "redemption" happening, outside of unverifiable statements from the book itself. So, unless you can point to this empirical evidence of yours that redemption actually exists and it only occurs via faith, then I would say the book is also 0% accurate on that point.
"Sin" is a construct of religious opinion and its existence is debatable. People can, and have been, learning to cope with and overcome what we consider baser instincts for thousands of years, even before your holy book came into existence. Civilization started developing because it was a greater survival strategy than chaos and opportunism, not because of a holy book. Though, religion in general did, of course, play a major role in the development of civilization. But keep in mind that Christianity and even Judaism were not the first or only religions to play a role in the development of civilization. There were religions that were old and well-established before the first word was written in what would eventually become the Bible.
Also, in my opinion, strict adherence to a moral code written two thousand years ago is a hindrance to the development of human society. Many things considered normal and acceptable even 100 years ago are now generally considered vulgar and unworthy of us (racism is a fine example of that). The difference between the morality of 2000 years ago and today is even greater. In areas that adhere to a strict adherence to centuries-old moral codes, things like stonings for adultery can still happen. This is behavior that is generally considered monstrous by the average member of a more religiously-relaxed society.
A holy book can't change with the times. And, by it's nature, it can't (according to most believers) be altered to fit the changing morality of society.
That said, I have no problem with people believing whatever they want to believe, and I am aware that wisdom, inspiration, comfort and learning can come from many different sources. Just because, in my opinion, the Bible and the Quran are outdated as guides for moral living does not mean that I think the lessons contained in them are useless or pointless. I just believe that they should not be your sole guide for living, and they should be read with the understanding that life was very different when they were written.