at what point did inorganic matter become organic life forms and what caused it?

[Creed of Heresy]

The reason for the term "atheist" is because to be a "theist" is the norm. Atheists are enormously outnumbered and tend to be the exception as opposed to the rule, thus the need for a title for discerning an atheist from a theist. Reason there's no such term as "astampcollectist" is because stamp collecting is not something practiced by the wide, sweeping majority. So hence, atheist/atheism is a term used to describe a deviation from the common stance of theism.

Simple as that.

Now as for the OP: I have no idea. Scientific evidence for abiogenesis exists and it gives a possible explanation but as to whether it actually happened, or when it did IF it did, the jury's still out on that.