They attend valid masses (usually Tridentine) and even participate in Holy Communion, unknowingly disrespecting God and the true Church all the while.
Traditionalist "Catholics" tend to have delusions of grandeur and overly high opinions of themselves. They are also the type of people who don't function well without a strong authority figure in their lives. Their protestant religion gives them the greatest authority figure of all: a vengeful God for whom mercy is a luxury gift reserved for the Traditionalist faithful alone.
Real Catholics feel kind of bad for Traditionalists, because Traditionalists act as if they are the true believers, and live life oblivious to the inherent heresy at the core of their beliefs.
Mark believes that the Catechism from the early 1900s is better than today's Catechism. Mark is also not very smart.
2. Mark is a Traditionalist Catholic
Mark is an asshole