Why is "creating a cake to be used by gay people" different from "hosting an event for gay people" in your mind? Why shouldn't you be able to skip out on doing either if you don't believe that they're morally correct?
If the cake is not inherently gay (ie, literally stating "I am a gay wedding cake" or some such similar wording) how is the creation itself any different because of the consumer? If 2 men ask for a pink cake with chocolate frosting and a straight couple ask for a pink cake with chocolate frosting, there's no inherent difference in the product, and thus in the production.
If it's "I will need to interact with and consult with gay people endeavoring to undertake what I believe is an amoral act (marriage)" then how is it different from hosting the wedding?
This whole area is arbitrary and nonsensical lines. We'll be better off when the same protective rights extended to visible minorities are extend to invisible minorities. You claim they're unrelated, I disagree. For now, the law agrees with you and I can concede that.
Again, seems like the baker was totally okay to sell the couple any of the pre-baked cakes, which would qualify as "creating a cake to be used by gay people".
The only difference is who the consumer is. Also, the hollow difference between "I created this just for you" vs. "I created this, and you will be using it" of your pre-baked vs bespoke cake example seems extremely weak to me. Legally, this doesn't matter, but hey legally at one point black people couldn't vote because "reasons".
The point I'm getting at: Why was OP comfortable with half measures? Why is "black" a protected class, even against "deeply held religious beliefs" but "gay" isn't? Why is "use a product you created just for me" different from "use a product you created"? This difference feel arbitrary to me, and grounded more in homophobia than any sort of sound logic.
Put bluntly: If you think gay people shouldn't be allowed to request cakes, I don't see how you can logically hold the belief that black people should be allowed to request cakes.