There were laws around about murder and theft many many years before Moses and the ten commandments
Indeed. G-d gave Adam seven laws which are binding on all non-Jews to this day--Sheva` Mitzvot Benei Noach (the Seven Laws of the Sons of Noah). But the source of these laws was Divine Revelation, not "human reason."
My whole point is that since the exact same stuff is going to happen whether or not there is a G-d (despite the atheist superstition that a rejection of G-d would create some sort of utopia), why is the concept of a Creator and Lawgiver so much more onerous than the same laws when imposed in the name of "human reason" and "social utility."
I'll take the one "fascist dictator" in Heaven (Who at least created the world) instead of the six billion potential fascist dictators down here any day of the week.