The comparison has nothing to do with bringing pizza to a gay wedding.Human rights are rights inherent to all human beings, whatever our nationality, place of residence, sex, national or ethnic origin, colour, religion, language, or any other status. We are all equally entitled to our human rights without discrimination. These rights are all interrelated, interdependent and indivisible.
Let me google that for you
They can deny service, but they shouldn't be able to deny service based on their own intolerance.
If they refuse to cater to any non-sacrilegious event or function involving homosexuals, then you'd have a case for discrimination.
Clearly, anyone who doesn't respect a persons religious beliefs, and chooses to take legal action against them because they refuse to violate those beliefs, is the definition of "intolerant". Not to mention petty, spiteful and juvenile.