So, anyone should be able to discriminate for anything?
No. Try reading what I've written already.
Discrimination is not wrong under the law unless the thing discriminated against is protected against discrimination. Moving forward I think resolution is in making it clear to business persons whatever are the rules regarding discrimination they must abide by. It sounds to me like the florist gal was not clear that under the law as a business owner she was required to provide a service contrary to her conscience. If this is the case then make it clear and provide folks a given period of time to get their affairs in order. Then the choice is stay in business, sell your business or close it down.