So using the logic that liberals are using, if a swinger couple wanted an Orthodox Jewish photographer to photograph one of their orgies, the photographer would be guilty of "discrimination" if he declined to service the event, no matter how politely he did so, because the swinger couple would note that multiple sex partners was their "sexual identity," their "sexual orientation."
A Bible-believing Christian would find it just as offensive to attend an event where gay couples were holding hands, hugging, and kissing as an Orthodox Jew would find it to attend an orgy.
YOU may think it's silly to find such things offensive, but you should have enough tolerance and respect for different beliefs not to try to force people to view things that you know they find offensive.