I have just noticed there is another thread on this, so I am copying and pasting my post on that in case of one disappearing!
It was the principle of the message they were expected to pipe on the cake, as I understand it, not the sexuality of the customers.
Imagine if a Jewish bakery were oblige to pipe an anti-Semitic message
Or a Muslim baker, something offensive to Islam?
Or you or I obliged to pipe some racist or anti- immigrant message
I think the verdict was the right one but no doubt there will be all sorts of protests for the wrong reasons
A customer is always perfectly entitled to go elsewhere.