When they extend back to a Founder who was Divine and rose from the dead to prove it.
(Sure beats a founder who was an occultist and Freemason from upstate New York, with a poor grasp of archaeology, a poorer grasp of theology, and an inability to keep his lecherous paws off the servant girls, doesn't it? Hey, you started this ...)
If that is the case, the Jews of 2000 years ago had every right to point at the new followers of Jesus and tell them they were a bunch of upstarts.
They did a lot worse than that. (St. Stephen the Protomartyr, pray for us.) Again, the only excuse for changing a Divinely-received covenant is when you receive a new Divinely-ordained covenant.
(Gold plates that nobody can produce, written in a language that nobody has ever heard of, relating events that never took place, do not qualify.)
You'll get no argument from me on that.
(Gold plates that nobody can produce,...
As if having the plates would prove anything besides the fact that there were gold plates. Would you then complain that Joseph was a fraud because he couldn't produce an angel on demand as well?
... written in a language that nobody has ever heard of,...
... as if every language that has ever been spoken on the planet in the history of the earth has left a record of itself...
... relating events that never took place,...
You can't prove a negative, at least, not without being omniscient. You can prove, however, that the first section of the Book of Mormon, which takes place in the Old World, betrays a posession of knowledge of Arabian geography (and other topics) which nobody can seem to explain in the case of an uneducated Joseph Smith.
... do not qualify.)
In your opinion. We do, however have the purported translated text of the gold plates, and it is a wonder in and of itself. Uneducated Joseph Smiths just don't produce a Book of Mormon every day. Write me another one yourself, just like it, if it's so easy to do, would you? If you can produce something that could pass as one of the sealed portions of the Book of Mormon, your anti-Mormon friends will pay you handsomely, no doubt.