I will guess that the Supreme Court decision on gay marriage, while hardly a surprise, was not the best news for earnest Christians. This is from the Times:
The dramatic shift in public opinion [on gay marriage], and now in the nation’s laws, has left evangelical Protestants, who make up about a quarter of the American population, in an uncomfortable position. Out of step with the broader society, and often derided as discriminatory or hateful, many are feeling under siege as they try to live out their understanding of biblical teachings, and worry that a changing legal landscape on gay rights will inevitably lead to constraints on religious freedom.
No kidding. Too many Christians vote for Republicans so progressives will double down on labeling them as bigots and homophobic haters.
On the other hand, the scene in the Charleston courtroom at the bond hearing for Dylann Roof was a stunning display of Christian love, forgiveness and witness. Here is Times coverage and a recent description (in the context of taking down the Confederate flag):
And, in the country’s most churchgoing region, Christianity played a potent role. White worshipers described themselves as pained by guilt and moved beyond measure after watching relatives of the nine victims in Charleston deliver an unexpected message, distilling the essence of Christianity at a bond hearing for the suspect: We forgive.
Although theology is far outside my operating area, my thought is this: if a devout Christian florist or baker is asked to work for a gay wedding, maybe he (or she) could say something like "That is contrary to my religious beliefs and I hope you can respect my desire to refuse, but if you insist then I forgive you and will pray that God grant both of us a greater understanding of his message and his love". That would be a more elaborate version of "Love the sinner, hate the sin".
And just to complicate the issue - my impression is that celibate homosexuals are not considered to be sinners (I also glean this from the same Times article linked earlier). Now, people get married for all sorts of reasons, such as creating clarity for legal, insurance, real estate and adoptive issues. And I daresay that few in the homosexual community are getting married because they had forsworn pre-marital sex. So (this is a logical leap, but hardly Beamonesque), unless there is a concern that the newlyweds will have sex during the ceremony, any sinning is entirely hypothetical and not truly contingent upon the wedding ceremony which might will be happening for other reasons. In which case, getting married is not, in itself, sinful, nor is contributing to it.