(No, it wasn't...you've haven't dug very deep into Lds history, have you? Well I have...because my Lds ancestors included a 19th century polygamist)
Polygamy wasn't banned in numerous ways; allow me to spell those out...some of which I already have in post #162...
Back in December, I posted this excellent Web site's historical look @ Mormon polygamy: Polygamy [Everything you might want to possibly know about historical Mormon polygamy]
Did you know, for example, that the first Lds president who wasn't a polygamist didn't come on the scene until 1945? (Even the Lds president who cracked down on new polygamist arrangements in the 1930s/early 1940s was a polygamist!)
Beyond that, let's take a look @ this chronologically:
1890-1910:
LDS leaders solemnized at least 260+ known plural marriages in the post-manifesto years when the church was pretending to be 100% against polygamy (source: Hardy, A Solemn Covenant, 1992)-- most of whom by either apostles like Taylor & Cowley (later ex-communicated) or by Ivins in Mexico, who was rewarded for this & made a general authority in the early 1900s, or by others who became general authorities after solemnizing such plural marriage vows. [So that gets it down under your 122-year-ago claim to the 102-121 year range...lots of living Mormons' grandparents & great grandparents]
1910-early 1960s:
Mormon leaders did not break up most of the polygamous arrangements that were already intact in 1890 & thereafter. B. Carmon Hardy shows in his book's appendix that some of those polygamous unions lasted into the early 1960s...some of those who were secretly solemnized in the early 1900s. [So, this covers the period of LOTS of Mormons' parents & grandparents]
1960s:
(a) Polygamy still psychologically accepted by Lds: Hardy cites a poll taken of mainstream Mormons: 40% say they would engage in polygamy if told to by their "prophet."
(b) Then, LDS apostle Bruce McConkie’s book, Mormon Doctrine (pp. 577-579 of 1966 edition, which was approved by the LDS First Presidency…unlike the initial late 1950s version which was not) says that polygamy will return to the Saints before Jesus returns. [Now we're down to under 50 years...lots of Mormons' parents & grandparents]
2012: Since I already covered this in post #162, I'll simply refer you there...Mormons believe there are Lds men alive now will become eternal polygamists.[Now we come to CURRENT Mormon practice, doctrine, and policy]
When the Mormon Jesus returns: As mentioned Lds "apostle" McConkie taught no polygamy "ban" would be in place. [Wow! Eternal lordship under Christ is a rather long time for Mormon polygamy, is it not?]
Mormons, themselves, are probably the best arbiter of this matter.
Here is a bit from a Mormon website, as regarding the matter at hand: "President Gordon B. Hinckley, prior president of The Church of Jesus Christ of Latter-day Saints made the following statement in 1998 about the Church's position on plural marriage:
"'This Church has nothing whatever to do with those practicing polygamy. They are not members of this Church.... If any of our members are found to be practicing plural marriage, they are excommunicated, the most serious penalty the Church can impose. Not only are those so involved in direct violation of the civil law, they are in violation of the law of this Church.'"
Here is the link: http://mormon.org/faq/practice-of-polygamy/
1910-early 1960s: Mormon leaders did not break up most of the polygamous arrangements that were already intact in 1890 & thereafter.
Why should it have been the responsibility of "Mormon leaders" to "break up" civil arrangements?
1960s: (a) Polygamy still psychologically accepted by Lds: Hardy cites a poll taken of mainstream Mormons: 40% say they would engage in polygamy if told to by their "prophet."
According to my calculations, that would mean that 60 percent would not do so.
If one presidential candidate were to receive fully 60 percent of the popular vote, would you not consider that pretty decisive?
Mormons believe there are Lds men alive now will become eternal polygamists...
To declare, boldly, that "Mormons believe" this or that, is to paint with much too broad of a brush, in my opinion.
It is a bit like one's declaring that "scientists believe in the doctrine of global warming," as if this were universally accepted among all scientists...