A pontificale...you are right. A high Mass...maybe.
But most Protestants (as well as, sadly, most cradle Catholics) don't have the theological background necessary to understand a low Mass.
...and unfortunately proper missals are more difficult to find nowadays.
Why must so much be understood Mark? It seems to me Christ taught..the people listened. There was expectation Christ would time and again share His words. Is this not what we attend church for..to hear what he might have to say to our hearts? How is it one must have a theological background to understand Mass?