This is what I understand: God's existence is scientifically unfalsifiable, meaning that you cannot prove God doesn't exist or disprove that God exists. But the point is this: science's being unable disprove God's existence is not proof that God exists.
To paraphrase Bertrand Russell's teapot analogy: let's say someone claims that there is a teapot revolving around the sun between Earth and Mars, and that the teapot is so tiny that not even our most powerful telescope can observe it. Given that we're incapable of proving the space teapot doesn't exist, does that mean we are supposed to accept the teacup's existence as a fact?