Why do people state "The big bang theory is proven" in answers without validation.?

That a big bang occurred is a fact supported by the COBE experiment. However the causal nature of what initiated the big bang is far from being understood. Current mathematics break down as you approach time zero. Initially there is no matter no time no space. Then the universe comes into being exponentially at colossal energy levels. The creation myths tell us this. For some thats a greater mystery.