Cool - say the 50,000 -100,000 are Mormons and Muslims, while the story you link says it's 50,000-100,000 Muslims, and doesn't refer to Mormons at all. No obvious bias there.
Wikipedia - really - a site where anyone can write anything they want?
Please - provide a real source for your claims.
You really do believe it is a myth?
I love when people still attack Wikipedia like they are in middle school in the early 2000s. Like, somehow, NPR can't "write anything they want".
But here is the citation, you know, that Wikipedia included as a footnote:
James Brooke. "Utah Struggles With a Revival of Polygamy. " New York Times [New York, N.Y.] 23 August 1998, Late Edition (East Coast): 12. ProQuest Newsstand. ProQuest. Brigham Young University, Provo, Utah. 11 Dec. 2007
Here is another one from that dastardly Wikipedia, but whose link is no longer active:
Brooke Adams, Fundamentalists: Most espouse polygamy as a tenet, but fewer actually practice it as their lifestyle, Salt Lake Tribune, 11 August 2005, as quoted at principlevoices.org, Accessed 8 June 2007
Another from the Salt Lake Tribune, which puts it at a lower number:
"LDS splinter groups growing" by Brooke Adams, August 9, 2005 – SLT Article ID: 10BF07C805DE5990