I actually do agree that acropora/ many corals feed heavily on bacteria, which is why powder food wise I primarily use benepets and am a big fan of carbon dosing. I did state above that Reef Roids was definitely not an ideal source of food for acropora.
However, in the study which I believe you are referring to, the experiment tanks and controls were semi closed systems, N/P was kept consistent and the non RAW systems were fine micron filtered which would limit suspended bacteria flocculant in the non RAW systems.
All the studies I have read point to Acropora absolutely being capable of capturing and utilizing the proper sized food items and not strictly just bacteria.
this is a post I made last time JDA was baselessly slamming coral foods. It contains links to multiple studies on the subject
Post in thread 'Caught Acro eating with polyps'
https://www.reef2reef.com/threads/caught-acro-eating-with-polyps.830833/post-8970867