First, that which we observe, that things are caused to exist, is a more probable premise than that which is assumed. Assumed means what? It is pitting a scientific principle against hearsay. Further, everything that is observed is in the universe, unless one has access outside of the universe.
The second law of thermodynamics tells us that energy degrades. Since the energy in our universe is usable, the universe has not be around long enough for the energy to all degrade, thus it can into being sometime in the finite past.
Yes the argument implies that what comes to exit was created, nothing uncreated has ever been observed to exit, the premise is constantly reaffirmed in science. Yes it does imply a creating entity, but that is not a fallacy, its the logic of the argument.