They being forced to take photos of a ceremony and celebration they find immoral due to their religious beliefs.
They're being paid to do a job. They're not being forced to marry someone.
And have the freedom to choose clients
With some exceptions in public accommodation.
Under U.S. federal law, public accommodations must be accessible to the disabled and may not discriminate on the basis of "race, color,
religion, or national origin."
...but
no religious Test shall ever be required as a Qualification to any Office or public Trust under the United States.