Today’s World & Everything In It podcast gets right to the point about the split between the conservative and liberal UMC:

REICHARD: The main issue cited for the split ithe denomination isame-sex marriage. But are there other issues odisagreement between the conservative and liberal factions? TOOLEY: There are many, many, many issues odisagreement within the United Methodist Church—sexuality ionly the superficial reason for the impending division othe denomination. But iI had tsummarize what divides the two omore sides ithat the traditional side sees the church ahaving a chiefly transformative role—evangelizing, winning new disciples tChrist, new birth, a changed heart, a changed mind, personal holiness and sanctification. The liberal side would see the church’s role aaffirming people where they are, creating ainclusive community, and working for social justice. (special character formatting from Reeder bionic reading mode)

Thus the reason stated is not the symptom; these must be differentiated. The real reason according to Tooley is the view of the church.