I really didn't want to get into this, but here I go anyways:
You can believe they are not, through the lack of proof to their existence, but there is no proof to the contrary either.
Contrary to the popular claim, an absence of evidence for an entity's existance is indeed evidence for the absence of the entity. As P(X or ~X) necessarily equals 1, any increase in the credibility you give to X has to come with an equal and opposite decrease in the credibility that you give to ~X and vise versa. If seeing some evidence would result in your assesment pf P(God) going up and P(~God) going down, the opposite happening, you not seeing that God-supporting evidence, means that your assessment of P(~God) necessarily has to go up and your assessment of P(God) down. And that still applies if you swap God for souls, heaven, newtonian gravity, quantumn chronodynamics and your stock market predictions.
Since we consistantly fail to see anything that would imply the existance of God, souls or heaven, our assessment of the likelihood of those propositions must continously spiral downwards as we grow more experienced, or else we are lying to ourselves.
That is a good argument, although I don't find it conclusive. You say it will spiral towards atheism as we find more proof for atheism, but is it currently all the way there? My argument is exactly that neither P(God) or P(~God) is 1, so we cannot state either as truthes. While one might be bigger than the other, necessarily lending that one more credibility, I do not agree that the stakes are stacked so high that we can proclaim is as the definitive truth.
The secrets of the universe is unraveling before ss without the explicit need of a god, but we haven't found all of the secrets yet.
Incorrect belief in the existance of souls and an afterlife and a merciful God who looks over you is very dangerous! People neglect their bodies, kill themselves and others, withhold medical treatment and consistantly fail to be sufficently cautious due to their unwarrented belief that the universe is fair and just when it really isn't, or that death isn't as bad as it appears because when you die you don't actually die for real, and that you'll be revived someday by magic that isn't actually going to happen. That sort of naivete is incredibly harmful, and people really would be better off without it.
I find no other option than to agree with this. It
is bad for people to rely on religion as their ultimate saving grace, and go all in on that front.
I can only think of two semi-counters to make:
Would those people be less naive, and better off, without religion? Is religion the fundamental cause to those people's actions, or merely an instrument through which they channel their naivety and immortality-complexes? Would removing religion not cause them to rely on something similarly vague and unrealistic?
Does the amount of people who take harm like this due to religion outweigh the amount of people who take joy in religion? Is this such a big majority that it would be wise to proclaim religion as false, and tell the people who relied on it for happiness and understanding to suck it up, or is it a minority so that it is more wise to simply make those few people be more cautious, instead of stripping away the sole meaning of existance from the majority?