It's good to know stance of firms
It is good to know where people stand instead of having laws that force them to act hypocritically.
Although I am an atheist and perfectly content for gay marriages to take place, I also have no major problem with Christian bakers declining to ice a sentiment that offends them.
Indeed, if I was wanting a cake expressing support for gay marriage, I should be pleased to learn that Ashers bakery opposes such marriage. I'd take my business elsewhere and encourage others to do likewise.