I think the difference lies in what will be required if sodomite marriage is made legal throughout the country.
Right now pastors do preach against the sin of divorce and there are many ministries devoted to helping couples stay married. No one seeking a divorce is attempting to makes those things illegal as a form of hate speech.
Neither are pastors required to publicly bless and agree that God says one’s divorce is not a sin.
Contrast that with the demands of gay marriage. It is hate speech to preach against it, conversion therapy has been made illegal in several states, and if gay marriage is legal no pastor will legally be able to refuse to officiate or have a gay wedding in their church.
Note that the attack is still against Christianity. None of the SSM merchants are demanding that a Muslim imam marry them. A resurgence of persecution has not been carefully guarded against, and apathy in the divorce arena is just one of many reasons for the resurgence.
I bet the number of divorced pastors is higher than the number of gays who are or want to marry. My point is that half of their interest in the issue is our reaction. They are like petulant children. Ignore them and the tantrums stop.