In ordinary contexts, pretty clearly, we don't countenance the possibility that something could come into existence without a cause. For example, if you and I were eating lunch, and a bunny rabbit were suddenly to appear munching on your salad, you would rightly dismiss the possibility that it popped into existence without a cause. So we need some justification for why, in this instance, we are going to want to admit a causeless beginning of the universe.
Craig does offer arguments that a personal agent was the cause of the beginning of the universe, but he doesn't say his argument proves that it is the Christian God. He got the argument from Islamic philosophers to begin with, so he knows better than that. He admits that he needs other arguments to get to Christian theism. Something powerful enough to bring a universe into existence caused the universe to exist, assuming you accept a caused beginning of the universe.
Now people have offered reasons for why an uncaused beginning is acceptable while an uncaused bunny rabbit is not, and that has to do with the fact that the BBT says there was no time before the beginning, and that Craig's causal principle need only apply if there was a prior time. So, the bunny rabbit needs a cause, since there was a time when it was not in existence and then it began to exist. But when there was no time prior to the existence of the universe, the causal requirement doesn't apply. This is a more serious objection than that which you have provided, however.
You should also note that plenty of people have challenged Craig, and he has responded to those objections. People like J. L. Mackie, Quentin Smith, Keith Parsons, Douglas Jesseph, and Wes Morriston have written objections, and these objection have been countered by Craig and his defenders, and you can't really get a sense of where the whole discussion is unless you look at how the debate has proceeded. Your responses, I am afraid, are re-inventions of the wheel.