The article essentially admits, by careful omission, the most important point: Mormons BELIEVE in polygamy as a sacred and eternal principle.
The article is careful to say that modern members of the LSD Church do not PRACTICE polygamy, while completely failing to mention anything about the HISTORY and OFFICIAL DOCTRINE of the LSD Church that clearly makes belief in polygamy an integral part of the belief system.
The article then concludes by confessing that the ONLY REASON that modern members of the LSD Church do not PRACTICE polygamy nowadays is because it's against the law and, for very practical reasons, the LSD Church finds it important to declare that they believe "in obeying, honouring, and sustaining the law."
So, yes indeed. They believe in polygamy. They have practiced it in the past. They would be practicing it now, if the United States government had not made it illegal for them to do so. But for PR purposes, they want you to think that there is absolutely no reason to associate polygamy with the LSD Church.
During an endowment session in the temple, one of the promises you make is to obey the "new and everlasting covenant", which is polygamy. We were taught in TSCC that we will be living polygamy, whether it's brought back in this life, or the next life.