The problem with the "don't like to talk about it" argument is that the answer to that is way too simple: Don't.
These threads are not a demand for information. It's a request. "Hey, anybody, if this has happened to you, please share."
It's not even a question directly to any individual, where you might feel awkward to refuse to talk about it.
If you don't want to share, don't. Not commenting at all means no one ever even knows anything happened.
Yeah, but if they simply don't talk about it, then how do they tell everyone they're a real life gunfighter and get everyone to think they're the expert? It's kind of tricky. They want everyone to know (or assume/think) they have been in a shootout, but at the same time they don't want to appear too eager to tell everyone. Your solution doesn't work...