It is a bit depressing to read threads and find that they consistently devolve to 'What about the Muslim point of view on this....?'.
Muslims (those sufficiently bothered) would believe that I am a cursed infidel in the first place simply by not being a muslim....the fact that I am gay would neither add nor detract from that; they would still be happy to take my money.
But trying (vainly, I suspect) to wrench this thread back round to the Christian opinion of the florist....No, personal religious opinions should not allow discrimination in the business world.