The Scriptures say that Jesus said the only unforgiveable sin is blasphemy of the Holy Spirit (I'll let you tell me if that's "Popery").
I do not judge the author; as I have stated in a previous thread, I know some Catholics who are "born again", i.e. have eternal life (just as I know many Protestants who do not know what it means to be born again, and so I worry about their eternal security and try to share the Gospel with them).
How is blasphemy of the Holy Spirit related to "Popery" as you call it? Blasphemy of the Holy Spirit is the rejection of His mercy.
No offense, but it sounds like you found your way into a stack of Jack Chick comic books.