This court case was all about Bounty under the guise of it being about polygamy.
I kind of see it the same way as how they finally took down Capone. Tax evasion is not why they wanted to take him down, but it worked so they took it.
Polygamy has been a thorny issue for almost 3000 years legally. Ancient Rome and Greece had laws against it. At times and in certain countries, those convicted could be executed. Religions both condemn and condone the practice.
If you really want a good education about polygamy in the real world, read the complete decision of the BC supreme court. You may not agree with the decision, but you will clearly see how it was arrived at. The court had to balance freedom against harm. The evidence of harm is legion: The restriction of freedom is marginal.
The complete text of the decision is at http://beta.images.theglobeandmail.com/archive/01344/Polygamy_reference_1344799a.pdf . It is a long read, but you will be better informed if you even skim through the issues.