I don't think that it is a misunderstanding. I think that it is an intentional untruth - albeit one not invented by the author you quote. Creationists never define what this"information" they are talking about really is in any adequate way. They never let us know how to know if it has increased or even give a reasonable argument to explain why it must increase if evolution is to succeed.
Obviously the whole argunent is a lie. For it to be true they would have to have such a measure of information. And since they don't have one they resort to vagueness in the hope that nobody will work out that their claims are unfounded
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