You are seriously mis-stating things here. Granted you were trying to write a quick summary, but still...
Some corrections:
"were the first people to settle the continents" -- No, Mormons don't believe this. For example, the Book of Mormon teaches that another group settled in the Americas 1500+ years prior to the Israelites ("Nephites" and "Lamanites") you mention. And many Mormons, myself included, believe that there were very likely other groups of people in the Americas as well that the BoM doesn't explicitly mention--including one or more of the current scientific theories such as are listed here:
https://en.wikipedia.org/wiki/Settlement_of_the_Americas
"Eventually all of the good guys were wiped out for their unrighteousness, but all of the bad guys that descended from the bad Laman survived" -- You are way oversimplifying matters by claiming that the light skinned group was good and the dark skinned group was bad. There are countless examples in the BoM of wicked Nephites and of righteous Lamanites, including long periods of time when the Lamanites as a whole were more righteous than the Nephites. There's even a prominent Lamanite prophet who prophesied the birth of Jesus. So it's not like it's a "Mormons believe light skinned people are good and dark skinned people are bad" type of thing like you are implying.
"went on to populate two continents" -- Again, many Mormons (such as myself) believe that the Nephites and Lamanites were just part of groups of people in the Americas.
"all Native Americans are just dark jews, genetic evidence notwithstanding" -- Thanks for the patronizing attitude, but you are wrong again. "All Native Americans have Israelite ancestry" might be a correct way of saying things, given how the Nephites/Lamanites are likely to have mixed with other groups. Note that saying "All Native have ONLY Israelite ancestry" would not be an accurate depiction of Mormon beliefs (this Mormon, anyway). And DNA evidence is perfectly compatible with the view that the Israelites are AMONG the Native Americans' ancestors, just not the EXCLUSIVE ancestors.
By the way, your implications that Mormons ignore science are just plain stupid, especially given the large numbers of Mormon scientists in the world -- of which I am one. And it's clear that LDS church leadership take science seriously as well. For example, in the not too distant past (1 year? 3 years?) they changed the official Introduction to the BoM to read "After thousands of years, all were destroyed except the Lamanites, and they are among the ancestors of the American Indians" instead of "they are the principal ancestors of the American Indians" as it used to say, I'm sure to better reflect what science has taught us. (See here:
https://lds.org/scriptures/bofm/introduction?lang=eng)