As a Lutheran that has studied the differences between Roman Catholicism and Lutheranism (which is not the same as Protestantism), there are not only differences between terms, such as grace, faith, righteousness, and sinner, but there are huge theological differences. If Lutherans and Roman Catholics were in essential agreement, then explain why Lutherans do not believe in purgatory or the invocation of the saints and Roman Catholics do? Why do Lutherans believe that the papacy is the AntiChrist and those that follow him are the kingdom of the Antichrist? The author of this article is delusional, and he is engaging in wishful thinking.
The author is making some real howlers, also.
Try this one on for size:
“All Christians agree that if we sin after Baptism, we have to confess our sin, otherwise we will go to Hell if we die with sin.”
I guess that might hold if the author eliminated all Calvinists and all Baptists who adopt the “once saved always saved” line. If that is the case, then the author is taking two steps back for every step he thinks he is taking forward with his ecumenism....
More likely, though, the author is just not very aware of other Christian traditions.