"I am not in a position to shed much light on why the C-802 was able to bypass Israeli defenses and strike their ship. "
It has already been reported that the anti-missile defenses were turned off because the captain did not know of a threat by missiles and because there were so many aircraft in the area.
I suspect a lot of assumptions are undergoing re-alignment, using Iranian TOE's instead of Syrian TOE's now, in light of precisely this development.
I also suspect that losses from using the old assumption set are not fully behind us yet.