I believe you are absolutely correct in broad terms here with nutrition and starving Zoa's. However, I have had nutrient levels range from 5-p03 and .03 p04 to 57p03 and .81 p04 between two tanks which still exhibited the same symptoms of stress with Zoa's which is why I felt the saying the low nutrients starves the tank idea was a little inconclusive or vague.Acropora rules.
It is sad to see but many reefers buy what they are told is the best.
In these cases it is the equipment that keep the water cleanest.
But many corals doesnt thrive in so nutrient defiecent waters.
I tell my customers to only have 1 turnover per hour through the sump and about one tank volume of air per hour into the skimmer. Dont use fleece filters ore aquarium computers.
In that way it is possible to have softies ad Zoantides with most stone corals.
And when you examine the values you slowly get a feeling how they fit together.
But if you listen to the Acropora people and buy things for 10 times sump turnover and 3 times skimmer air intake your softies will starve to death.
Most corals need both organic nutrition and inorganic.
The best organic nutrition i believe is fish poop (corals are adapted to that since more than 100 million years) but many Amino bottles are also good.
I believe most of the big coral growers mix their own coral food of fish meat, shrimps, mussels and various other living things from the sea. And check the inorganic values too.
It is not a coincident that the zoanthids did recover in snoopdogs other tank with hang on back filter and no skimmer.