Avi….
Why are you assuming the marriage ceremony takes place in the banquet hall. It may very well take place at City Hall. Chances are that a same sex couple will not be looking for a frum catering hall to hold their celebration affair.
The government can’t make any non-government employee perform a marriage ceremony. We are not slaves of the government.
Not every one who performs marriages is ‘licensed’ by the government. This varies from state to state. Here, in Connecticut, any ordained in state clergy can perform a marriage ceremony. The couple still needs to procure a marriage license from the Town/City Clerk’s office where the ceremony will be held, and record it with the Toiwn/City Clerk in either the locale where it was issued or the new residence municipality (In State) of the newlyweds.
Frum people who bring in a clergy person from out of state (very common, my daughter was married here in April and the Rav was from NY) typically have the Town/City clerk perform a civil ceremony when picking up the license, or have a Justice of the Peace (I’m one) perform one, then have a religious wedding ceremony later.
Judges don’t generally make a habit of performing marriages unless there is a personal connection to the couple or their families.
AND absolutely none of this has any bearing on a choice of Presidential Candidate. This is all settled law in the USA.