In one case it's a message of love. In the other it's a message of hate. You're personally welcome to treat them both the same, but I think you'll find most of society will treat the messages very differently.
If you can't understand why I'd imagine you're going to spend a lot of your life being extremely confused, angry and frustrated.
(I can't see the flagged post that's at the top of this subthread so if this is a bit out of context that is why)
If the baker thinks it's a message of sin, then what? It's not like selling them a room at a hotel or any other standard thing. This is a custom crafted item and message that they are being asked to help propagate, and one that they disagree with.
What exactly is your point? I would hope a baker would treat someone who they feel is sinning by being in love with the "wrong" person, differently than they treat someone who is advocating for the elimination of an entire group of people due to their race or religion. ESPECIALLY given that the baker believes in sin because of their own religion...
The fact you're equating the two is actually disturbing.
If you can't understand why I'd imagine you're going to spend a lot of your life being extremely confused, angry and frustrated.