That's one of the big questions religion tries to address, whether it's deism or Christianity: Why are we here at all? The deist position is generally that if there wasn't a Creator, there would be no Creation, because the default state is Nothing.
And...I'm not sure what the atheist response to that is, aside from asserting that the default state is Something instead of Nothing. I don't see how either of those ideas is inherently more sensible than the other.
The correct response to that is to inquire what created their Creator. The most common answer is "Nothing" or "It always existed", breaking the chain of cause and effect just as easily as a spontanious generation of the universe without a creator would. This renders the point null.
I disagree. Yes, it breaks the chain of cause and effect, but we don't have any specific information about a Prime Mover that forces it to have a starting point. The universe, on the other hand, has a very well established starting point. In other words, I can accept a God who always was, but a universe that always was defies all the evidence as we know it.
Indeed, we don't have any specific information about a Prime Mover. In fact, we don't have
information about a Prime Mover, and I suspect that's because it's just
made up. If God doesn't require a starting point, the Universe doesn't either. It doesn't get any special pleading in the name of being "magic", or whatever variable you prefer. I'm sorry if I sound harsh here, but I'm simply tired of hearing this same argument over and over again whenever we don't know somthing. The universe,
our universe at least, does have an established starting point in time, but that doesn't prevent it from having generated out of nothingness. I don't personally think that's the case, however. Things get really strange when you start speculating about the begining of our universe. Time as we know it may not have existed. We know so very little on the subject, but jumping off of that to decide that a Prime Mover exists or that the universe always existed is simply not good science. We just don't know the truth yet. Deciding that it must be some supernatural force instead of searching for that truth will get us nowhere.