You can have memories of events happening without actually being at the event.
Name an example of an event you remember that you weren't physically there for.
I think he means, and please correct me if I am wrong, but I think it goes something like this, I wasn't present when John Wilkes Booth murdered Abraham Lincoln yet in my minds eye I have a pretty good memory of what I think it must have looked like based on things I have read, TV and movies reenactments and so forth. I wasn't at the Pearl Harbor attack or JFK's assassination but I have read and seen enough video to give myself a working memory of the events.
At least that was the way I understood the earlier post.