Mental masturbation is fun, and there are good reasons for it. Its part of our thinking abstract, its helped us think deeply about things that won't, wouldn't, shouldn't and or don't matter, in case of the future chance they might. It's made us a very successful species.
Their claims are way too fallacious and assume way too much.
Claim One: Why does it require a god? Why not a dragon instead? Or a fairy? What is a god and what makes him fit for the job? And why exclude the possibility of an inequal distribution of matter and antimatter, or other possible events? Why exclude the likelihood that there are an infinite number of universes, making one part in ten billion too equal out to being an infinite number of universes just like ours?
Claim Two: Why look at the universe in a biocentric fashion? How do we know that the universe wasn't finetuned for atomic explosions? Afterall, most matter we see either has or will go through such explosions, in a star. We have life because our universe permitted it. But again, what would make God worthy of such a task? Why not a dragon or a fairy instead? Why throw God into the gaps?
And with an infinite number of universes, there are an infinite number of such universes that permit our type of life. However, its possible for other forms of life to exist in other universes with other laws and conditions. They also assume that this, in this universe, is the only possible type of life.
Both claims are erroneous and self-invented bs that have no data to support them. They are playing the odds game, or the game that it's too improbable for it all to have happened by "chance".. Well, It's a good thing we understand our science because they are typically science illiterates. It's the pleading for your ignorance.
If you want a good laugh on such arguments, go watch the video series "Why Do Creationists Get Laughed At?"
If you want some good insight into how our universe works, or is. I can provide a somewhat informative post here. Just let me know if you want me to do so :)
If claims one and two were refering to a closed system of opportunity, numbers like "one in a billion" sound impressive.
But, in a limitless system of opportunity (or even a system with unimaginablely high numbers of opportunities)... such statistics are piss in the ocean! In fact, in a limitless system, where all possible outcomes have opportunity to manifest, the odds of the universe and life manifesting are 100%.