It happens in trad churches, too.
Satan is an equal opportunity employer.
Yes, but as I've said a thousand times, there's a difference between a PROBLEM (which could be random, due to human nature, etc.) and a FUNDAMENTAL PROBLEM with a group, which is caused by the very nature/charter of the group.
For example, it's fundamental that the Conciliar Church is open to the Modern World: thinking like it, respecting it, updating its doctrines and practices to better suit it, etc. This is not true about the old SSPX or current-day SSPX Resistance. You might find worldly people attending their chapels, yes, but they would be doing so IN OPPOSITION to everything the group stands for
. See the difference?
You can't blame a group for failing to control members who are rebellious and refuse to obey. What can the organization do when their authority is denied? The only answer is to judge an organization by its officials, its leader, and its charter -- the fundamentals of an organization -- what defines
an organization. An organization is certainly not defined or summarized by the behavior of its rebellious or disobedient members!
When a Conciliar "catholic" is worldly, he's being a good Conciliar "catholic".
When a trad is worldly, he's being a bad trad (going against the teachings of his priests, the organization that runs his chapel, the beliefs of his fellow-parishioners, etc.)