You have asserted this multiple times, however, you haven't demonstrated or explained why what you say is true. If plural marriage is an abomination we could (and we do) have the Abrahamic Covenant (whatever that means to you, but just using your words).
Leaders and people of every stripe, gender, culture, race, class, etc. can make horrendous mistakes and be in error.
Are you saying that because something good resulted in a condition where people practiced plural marriage, plural marriage is good? Is this what you mean or is that what you are trying to say.
Please, explain why your assertion is true.
-Finrock