We already have an unofficial polygamous culture in America, in case you didn’t know. It’s called welfare communities.
Even if you can’t do the math (1 + 1 = 2), just look at the muzzie societies, where the rich have 4 wives and the poor men are all practicing fags who publicly denounce fagness and many of whom become terrorists who willingly blow themselves up to get 72 virgins.
The surplus male problem is also a serious exaggeration. You left out the option of both men and women having affairs. It does happen. In addition, there is also serial divorce and remarriage. There are plenty of unofficial polygamists in the United States, only unofficial because they don’t have a legal marriage license, these would include your typical Hollywood Superstar (serial marriage, promiscuity, affairs, multiple families being supported, etc.) I would actually be surprised with all of this non-monogamous behavior, that the U.S. doesn’t have a serious surplus of men already. The primary reasons I have found for a male surplus have been more related to abortion than polygamy.
As for this situation, the worst crime these people commit, IMO, is cutting themselves off from the rest of society, and the fact that it isn’t a problem for so many people to tolerate someone living in our nation yet not taking part in the processes that affect the rest of us as well. Just about every other problem that they have comes from this.
The State of Texas would disagree with you. They contend that aggravated sexual assault of children is a serial problem with this group. The juries that have heard the evidence agree with the State.