http://reefkeeping.com/issues/2003-10/sp/feature/index.htm
Is from 2003. It says,
The medicated foods are a good option for use as a preventative, for mild infestations, or when used in conjunction with one of the other less effective treatments, such as biological controls
I see no scientific basis here. Nothing says it cures it, just that you won't see it anymore. If you did nothing, and the fish didn't succumb to the disease, you will also never see it again, even though the fish is tortured by it. The doctor you asked for said there is no scientific evidence it helps. The only cited evidence about Metro in there was that it possibly hurts the fish's digestive system. Specifically
could have deleterious affects to the beneficial microflora of a fish's intestine, much like the side effects to Copper exposure (Dr. Charles Moon, aka moonpod, pers. comm.)
As for your second source
http://www.aquaticcommunity.com/disease/marineich.php
Now this one is just full of wrong. Let's start with their effective cures,
The least intrusive way to treat this disease is by changing 50% of the water each day for two weeks. This removes the parasites. This method is most suited to be used for treating one fish in a hospital tank and not for an entire aquarium. It is very important to match the temperature and salinity of the old water when using this method.
It doesn't even take into account the full life cycle of Ich,
http://www.reefcentral.com/forums/showthread.php?t=1992196. The entire time you're doing these stupid half water changes, the Ich is just on the rocks/glass/whatever dividing. There is a ton of Ich in the water, and you think 50% water change is going to remove it??? That's just ridiculous.
It gets better though with this statement,
Mild cases of marine ich can be treated biologically with the help of cleaner shrimp. Cleaner shrimp can also help prevent the disease from ever erupting.
Ich is under the skin, and as noted many times, Cleaner Shrimp do nothing for Ich, as noted by this response
http://www.reefcentral.com/forums/showpost.php?p=9385241&postcount=8
These are old sources, the second with wildly inaccurate information.
Until you provide something more current, it's plainly snake oil.