You are a scientist, and so it makes sense that “How?” would be the foremost question on your mind. Yet just because “How?” is the only question science is equipped to answer, does not that mean it is the only one worth asking. Just because science can't answer the “Why?” does not make it an invalid question. Is it appropriate for science to rule out intentionality in the universe simply because it can't study for it? If that is the case, then I wonder, what place does the question “Why?” have anywhere in our world, and why on earth do we humans persist in asking it? Have you ever honestly considered that there may be some questions which science can never answer, because they are not matters of science at all? How do you account for art, for literature, for philosophy, for all the humanities? Can science explain all these and the deepest and highest aspirations of the human soul? Can science explain why life fights to be lived and to perpetuate itself? Can it explain why there are laws in the universe without which science, along with all the things it studies could never exist?
You've devoted your life to undermining belief in God - to dismantling, if possible, any faith that has been placed in Him. I know you believe you're doing a good thing. You are setting people free from slavery to superstition. You have your own gospel – the good news of freedom from the knowledge of God. Yours is a world where each life's meaning is a blank slate waiting to be defined by whoever is living it. After this life there's nothing - nothing to account for, no one to answer to, nothing to fear, nothing to anticipate. The freedom your belief system offers comes from knowing that. It is the freedom to live each moment to the fullest and according to your own terms.
I have allowed my imagination to run wild with the freedom you describe. I've thought long and hard, wondering what would be the way to live if this is all there is, if there is no God, no judge of the universe, no standards, no accountability, no ultimate right or wrong, no punishments, no rewards. There would be no sin, that is true. There would be no guilt, also true. There would be no fear of future judgment. There would also be no reason to respect human life or laws, other than to suit whatever instinctual emotional tendencies I may have, or to avoid society's established penalties (the value of which is hard to establish if there is no purpose in the universe). If men are not created in the image of God, then there's no reason for me not to detest any person of a color not my own, or of lower intelligence, or one who is uglier, or crueler, or kinder, or more beautiful, or richer, or weaker, or older, or sicker.
In fact, we might as well give up talking about human dignity, of the higher good, and the perpetuation of the species. What on earth difference does any of that make? If it's all just random, what difference does any of it really make? I am of no more value than an amoeba, a speck of dust, or a puff of smoke. There is no benefit, or lack thereof in the continuation of any species, or of this world as we know it. There is no reason for me to watch my language, to be kind and gentle, or to seek not to offend. As for those who suffer around me - there is no reason to feel anything but glad that it is them and not me who is suffering - unless of course I could think of something tangible to be gained in assisting them. There is no reason for me to love anyone except to the extent that they please me, and only for as long. There is no reason for me to love my children or care for them, except that pesky maternal instinct which inexplicably and without purpose insists on perpetuating the species. There is no reason not to abuse them or even kill them if I want to. There is no reason for me not to seek revenge if I feel "wronged" - though how I could be wronged, when there's no such thing as right - well.... (If I don't make it "right", who will?) In a godless world all there is for me, a being formed by random happenings, is to follow my moment by moment sense of pleasure and pain (though why I would interpret one as "good" and the other as "bad" would also be a mystery) - or, as the Scripture so nicely says: "Eat, drink, and be merry, for tomorrow we die".
I could go on like that, but I hope I've made my point. Your godless gospel, if wholeheartedly embraced and consistently applied, leads to destruction and death. But then, if your view is true, I suppose it doesn't really matter after all. And then again, if it is true, it shouldn't matter so much to you what I or anyone else believes either.