Phobias could be split into two distinct categories:

1. Unjustified Phobias: Phobias that are not justified and make no sense due to the target being of no harm. An example is fear from cats (Ailurophobia).
2. Justified Phobias: Phobias that are justified due to the target being (mostly) harmful and should be avoided.

If Mercola’s advice could result in inducing chemophobia on part of the population, then this is not Mercola’s fault, its the chemicals’ fault, and in this case, a phobia will be beneficial.