But you said: "Anyone who claims to be a Knight Templar today is a member of a secret society and is, if Catholic, under a latae sententiae excommunication"
Talk about a distinction without a difference....
L
The distinction is quite differentiated.
The original Knights Templar were not a secret society, but a religious order established according to the norms of canonical law.
Anyone who claims to be a Knight Templar today cannot claim membership in the original Knights Templar, since that order was dissolved as a canonical organization centuries ago.
The "Knights Templar" today are any of a number of secret societies that claim to be somehow occultly linked with that long-dissolved order. There is, of course, no actual, historical link.
Membership in a secret society incurs a latae sententiae excommunication.