No one knows why we are conscious. We have sliced the brain up a thousand ways and we will slice it up a million more and will never find consciousness because it is an emergent property of healthy brain, just like light is an emergent property of a working light bulb. No matter how you disassemble a light bulb, you will never find the light, though I grant you'll eventually figure out how light is produced, the assumption that a light bulb contains light is wrong headed. It's just a metaphor.
There is no worse slander than the truth: Strong AI can not be achieved, not with digital computers and programming and machine learning, and most likely by no other method either. Please, please grow up, and set aside your childish beliefs, because we need you now more than ever, here, in the real world.
Regardless of the details of how a brain is a conscious, it can be reduced to its constituent pieces or nuts and bolts, so to speak. Everything from the electrochemical potentials within neurons to the encoded chemical information in the form of DNA and RNA that spontaneously replicates and orchestrates a maddening array of complexities, we can partially explain. Even if our explanation is basically parts in a bucket, that's enough to paint a future where humanity understands enough of those processes to replicate consciousness without actually understanding why it works. Perhaps we don't need to understand the emergent properties, but merely discover them like the standard model in physics. We equally can't explain /why/ the fundamental physics constants are the way they are, but we can use them to do extraordinary things.