What's to understand? You said that the author's position that G-d spoke to the entire nation was based on the movie rather than the Bible.
In the movie Moses went up to the mountain alone and heard G-d speak. According to the Torah this is not what happened. All Israel heard the voice of G-d.
I get the feeling NewJerseyJoe doesn’t realize that he got it backwards or a least is communicating his comment backwards.
The author says that ONLY Judaism teaches that God revealed His commandments to the entire nation (not just to one man). Christianity teaches this same thing very clearly; it's in the book of Exodus.
The statement that "only Judaism" teaches this is absurd. As I said in my first comment. The author obviously has no "understanding" of what Christians believe or don't believe.