Just watch the news, especially these news show panels. Once you begin to realize what the logical fallacies are you will begin to spot them on the talk shows regularly. When you see these shows such as "The Five" shown on Fox News featuring people like Bob Beckel espousing nonsense and outright lies that should have been easily overcome by his colleagues you begin to realize that these talking heads have no clue. As a result even the ones holding the right views and concepts are intimidated by the Beckels of the world.
The masked man fallacy is an illicit substitution of identical: the substitution of identical designators in a true statement can lead to a false one. This fallacy is a of formal logic in which substitution of identical designator in a true statement can lead to a false one.
One form of the fallacy may be summarized as follows:
Premise 1: I know who X is.
Premise 2: I do not know who Y is.
Conclusion: Therefore, X is not Y.
Please follow the link for the explanation. RK