Let's suppose following statement is true:
"A chance hiccup in the tranquillity of being, so it is posited, produced a big bang in the cosmic nothingness and created everything; time, matter, energy, life, consciousness, morality!" (Source.)For argument's sake we agree that the hiccup was a mere accident - that the striking of all those variables at the right time produced the world, in itself a statistical miracle - and that it was unplanned.
We cannot deny then that there was something in the things or in the nature of things that had the 'blue-print' to give birth to 'everything'. That even if no one was in control, who wrote that code or made that seed which burst forth all of its secrets into living realities? To deny the creator or to say who created the Creator is like solving the mystery of a ball of thread which has no head! Hence, the most optimal solution to this problem can only be affirming existence of One God.
Theory of accidentalism would have been fine if it remained neutral, but its following claims are more illogical and abdicate the very theory:
"The universe is thus devoid of any goal, meaning and purpose save that created by man. Man’s humanity, his morality, art and science, are nothing but gifts of the biological struggle, chance benefits of man’s effort and genius. For his genesis and existence, therefore, man need be grateful to no one but himself because it is Man not God who is the creator of man’s humanity!" (Source.)