How can an Anglican clergyman, who has sworn to accept the Articles of religion, teach such doctrine?

I do not see how he can do so. Romish theologians are simple children compared with the capacity for mental gymnastics manifested by Rev. Vernon Staley, the author of the book, in his efforts to salve his conscience. He says in effect that the doctrine of purgatory is all right, but that Anglicans must not use the word purgatory. He admits the thing, but not its description. He calls it a place or process of cleansing, but he will not call it purgatory, which means the same thing. It is as if we Catholics had invented the word theatre. Then this exponent of Anglicanism would insist upon using the word play-house, and swear that he did not agree with the Catholic Church concerning houses of entertainment. In substance he declares Article XXII. to be false and unscriptural.

Radio Replies Volume 1 by Rev. Dr. Leslie Rumble MSC and Rev. Charles Mortimer Carty