[How would you define 'mysticism' in the context you use?]
Basically, add on doctrines and false scriptures that are not the Word of God but rather the traditions and fables of men who withstand the word of God.
That's a charge Protestants and Catholics through at each other and repeats your other claims; I don't undertand your addition of mysticism to it.
Is this the total of your understanding of the Christian mystics?