Your entire argument consists of wishful thinking that is a luxury accommodated by your ignorance.
There is no doubt that Joseph Smith had sexual relationships with many, if not most, of his wives. The LDS church itself made that clear when it reacted to Joseph Smith III and the RLDS church's denial of these facts by obtaining statements from Joseph Smith' still living wives.
There is also no doubt that he married women who were already married to other men, and who often remained married to those first husbands, as well as Joseph Smith. Ironically, the DNA evidence looks the most promising for one of those polyandrous wives, Josephine Lyon, daughter of Sylvia Sessions Lyon, at least according to this:
Ongoing research includes evaluation of Josephine Lyon (Sylvia Sessions Lyon) autosomal DNA. "Hundreds of DNA samples from male and female descendants of both Josephine Lyon and Joseph Smith have been collected and are being analyzed with the objective of identifying lineage-specific markers..." (Perego, Woodward, Journal of Mormon History, Vol 32, No.2 fn 39). Descendants of Josephine participating in this study have indicated the research is "promising" in confirming Josephine as a daughter of Joseph Smith. The researchers are also hoping to study the other possible children of Joseph Smith and welcome the involvement of descendants.
http://wivesofjosephsmith.org/DNA.htm
Frankly, given the fact that this would be a proven child of a polyandrous union, I doubt the final results will ever see the light of day.
Now, you have a choice, given the statements of Joseph Smith' wives. You can choose to regard them as unrepentant liars, or you can take them at their word when they assert that Joseph Smith had sexual relationships with his wives.
From the same site:
Because Joseph Smith practiced polygamy in relative secrecy, the details of children he may have fathered by his plural wives is uncertain. In a 1905 speech at Brigham Young University, Joseph's wife, Mary Elizabeth Rollins explained, "I know he [Joseph] had six wives and I have known some of them from childhood up. I know he had three children. They told me. I think two are living today but they are not known as his children as they go by other names." ("Remarks", April 14, 1905, BYU Lee Library).
Josephine Lyon, daughter of Sylvia Sessions Lyon, wrote, “Just prior to my mothers death in 1882 she called me to her bedside and told me that her days were numbered and before she passed away from mortality she desired to tell me something which she had kept as an entire secret from me and from all others but which she now desired to communicate to me. She then told me that I was the daughter of the Prophet Joseph Smith”.
Obviously, his wives did not know just how many wives Joseph Smith had.