Except that Trump is saying that “a lot of people must have died” because it was a major river crossing and that is where that things like that logically went down according to him. Reading between the lines what he really means it that this must have been a prime battle site because it occurred in a place that now happens to be the location of his golf course.
The plaque, which happens to have his name on it, says that.
Again, it’s doubtful that Trump is a Civil War hobbyist, let alone an expert. It’s doubtful that he personally researched the matter and likely that he just accepted someone elses overembellishment of the sites significance.
It happens. I have a LOT of friends in the area who incorrectly claim that their houses sit on the site of some battle or another. Not because they are lying but because someone else told them that.
It’s very much like a game of telephone.