I don't have speakers on my pc so can't hear what he says but I am guessing he is American. If he is then typical stupid American thinking using antibiotics to treat a photosynthetic bacteria in an aquarium.
There's enough problems with drug resistant bacteria killing people, animals, birds, fish and reptiles as it is. We don't need to make the problem worse by using antibiotics designed to treat people, to kill things in the fish tank. That just adds to the drug resistance problem we already have.
Blue green algae (Cyanobacter bacteria) can normally be controlled by reducing nutrients, especially dry food, and by keeping the tank clean. If you have major problems with it in tanks, perhaps check your tank maintenance schedule and see if it needs improving. But antibiotics should be the last thing used for this issue.