I've never understood why those cake bakers can't exercise their conscience rights without making it an affront to the gay/lesbian couple.  It is a standard business practice to find ways to politely and vaguely demur when disagreeing with a client:  "we are not able to accomodate the date and venue you had in mind," "we can't fulfill your request at this time and would like to refer you on to a business associate who can meet your needs," etc.  There are ways of choosing not to do something that would violate your beliefs, without disclosing all the detaills to another party who might be offended.