I think he means to say the public disorder resulting from Alexander's death and the division/warfare between his generals and their stakes on the empire. Alexander was also seen as a sort of "evil tyrant" by the monotheists, not unlike the "anti-Christ" Hitlers and Napoleons; this was because he was extremely repressive in Persia, destroying libraries and great works of art, and he especially persecuted the Zoroastrians and had their books and holy items burned. Whether this was attributed to him being the bringer of all death and destruction in a religious sense, I don't know, but he sure did bring a lot of death and destruction.
And I think the guy was meaning to say that every few years there is a "judgment day" fear. The fall of the Romans, the Black Plague, etc. This is all God of the gaps. Shit happens; very bad shit happens, mostly because of nature, sometimes because of human actions, but shit happens, and many times there is a lot of speculation thrown around them. Nowadays speculation happens less because of science, but then again, science answers to those who fund it, and those who fund it can be both secular or religious ("Christian Science"). Most people cannot come up with an explanation for catastrophe- either they don't know all the facts or lack the education to make a logical theory of what they do know, and so they look to the supernatural. In the gaps lies God. It doesn't make sense to me, so it must be God/Supernatural/End of Days. That's the idea.
