(Author here) Thanks for explaining this more succinctly than I can :)

Just one nitpick:

> decent amount of stuff that has to be done in main before you run _start

should read

> decent amount of stuff that has to be done in _start before you run main

Analogously, cleanup code like running global destructors usually happens in _start/CRT after main returns, but I skipped that in the post for the sake of brevity.