Swords in Pre-Columbian America

“And it came to pass that thousands did flock unto his standard and did take up their swords in the defense of their freedom, that they might not come into bondage.”
Swords in America? Evidently the mayans had a sort of club lined with sharp shards of Obsidian that would cut flesh, and the Spanish called these swords in a few journals. That is the defense FAIR gives for the use of swords in North America.
I have a couple problems with this.
When Nephi left from Jerusalem, Metal swords had been in use for quite some time. Nephi himself supposedly set up forges and was forging steel. So this is a culture that would have known a little bit about swords and how to make them. And there is no mention of this art being lost. So why would these swords be the vastly inferior clubs lined with obsidian?
The second problem here, is that Joseph Smith, the supposed prophet, was under the impression that the Book of Mormon took place in North America. So you have to maintain that Joseph Smith was quite incredibly wrong about the location of the events recorded in the Book of Mormon if you are to relocate the events to South and Central America. In fact this would make him so wrong as to question his legitimacy as a prophet. If he isn’t right about the past, how can he be right about the future? Exactly how fallible can a prophet be before he is recognized as a charlatan? Just asking here.
When did these advance civilizations of the new world lose the art of forging swords, and why? I mean making swords has been for the better part of the history of man an essential skill for a civilization to have, especially if their neighbors have swords. So in an isolated context like America where no one knows how to make them, it isn’t essential. But when your neighbor can make a better sword than you can, well then he becomes your master. That is what history teaches us. So sword making isn’t a skill you lose once you have it.