It's been brewing for decades. In 1972, the United Methodist Church added a declaration that it "does not condone the practice of homosexuality and considers this practice incompatible with Christian teaching" to its rulebook, the Book of Discipline . Such sentiments were unfortunately typical of the time, though by no means universal. Homosexuality, some argued, arose from demonic influences, or was a communist plot, or was at best a step removed from rape and pedophilia, or if nothing else was unnatural and disgusting.
This language, and related language barring LGBTQ+ people from holding leadership positions, have lingered in the rules ever since. Enforcement, on the other hand, has been inconsistent. This upsets those who have an attachment to these rules, and such people often insist that the rules must have teeth.
In the meantime, though, the position enshrined in the Book of Discipline has become increasingly controversial, as heterosexist attitudes have over and over proven to be unjustified. And so some within the United Methodist Church have participated in or outright performed gay weddings, in defiance of the Book of Discipline, even before the United States Supreme Court affirmed marriage as a civil right for all consenting adults, regardless of sex or gender, in 2015. There are openly LGBTQ+ clergy, too, including a lesbian bishop in the Pacific Northwest Conference of the Western Jurisdiction. In everyday life, more and more people within the church, even if not gay, lesbian, bisexual, transgender, or whatever else themselves, have found that they have friends, neighbors, and family members who are. Many feel, too, that the attitude of exclusion embodied in this policy runs contrary to the very nature of Christianity.