It is just a reductio ad absurdum of the posts it was responding to, wherein anything can be ascribed as a "cascade of events" with no clear place to to pick the root.

While you can model the world like this, one of the issues is often determining the "first mover", as it is hard to reasonable assert that the complexities of our world are primarily caused by primordial ooze. To continue the reduction, someone could come and say "Because a molten earth" after "Because primordial ooze" and there isn't necessarily grounds to refute that if the "Because primordial ooze" point was accepted.

No it’s about where does one draw the line to events that led to the present situation.