Baking the cake is
not a form of Agape “love,” a Jesus love, a Christian love. Rather, it is validation of an immoral arrangement which Jesus thoroughly repudiated by embracing Mosaic Law comprehensively.
Baking the cake also mocks genuine, actual marriage (as opposed to baking one for a previously fornicating couple who decides to validate their marriage by now formalizing it in a genuine marriage, thus repudiating, by that action, their previous lifestyle).
For a practicing Catholic or believing Christian
who understands the way Scripture actually works, and how the silence, in the Gospels, about homosexuality, indicates the opposite of assent for the behavior, baking the cake is:
Emotionalism
Sentimentality
Political Correctness:
‘Hey man, I’m cool/You’re cool.’ 
Moral Cowardice
And it is the same for any other believer, as well as an agnostic or atheist who objects to the artificiality of SS “marriage,” yet concedes to bake the cake for monetary reasons or the reasons above.