The Supreme Court — the highest court in the UK — has considered all the details of the case at great length and reached a decision.
The only puzzle if that the lower courts could have thought otherwise.
The baker was asked to use his skills to produce a cake with a slogan promoting gay marriage: it was NOT simply the case that he was asked to bake a cake that would be used at a gay wedding.
He did not wish to do so. The court ruled that he has that right. Victory for common sense.