I really enjoy The Journey Home also. Many Protestants, including the Church of Christ, subscribe to the notion of Sola Scriptural, which means that scripture alone is authoritative in matters relating to faith and morals. You said “the Church is Sacred Tradition” which is not quite accurate.
As in many things, the Church takes a “both and” approach on scripture and tradition. We believe in Sacred Scripture, Sacred Tradition, and the magisterium of the Church as the three-legged stool of authority in matters of faith and morals. We also believe that all three fit together and there is no contradiction between one aspect and another. In other words, Sacred Scripture, read in context, does not contradict Sacred Tradition, and vice versa.
In reference to Mark 7:13, it’s useful to look at it in context
So Jesus was condemning the Pharisees because their tradition (not supporting their father and mother by saying qorban) was in contradiction to the 4th Commandment. So he’s not condemning the idea of tradition, but the fact that this tradition (and others they practiced) was contrary to the Word of God.
In fact, St. Paul tells the Thessalonians
So traditions in and of themselves are not the problem. Protestant churches have their own traditions, like electing elders, Lord’s supper of grape juice and crackers once a year, or whatever. The difference is, our traditions are based on what Jesus taught, like the Eucharist or venerating his Holy Mother.