You don't have to agree but you have to treat them equally as you would the rest of the public if you are going to offer services to the public. You don't want to bake a cake for a gay wedding don't offer your wedding cake services to the public. Simple as that
They aren't asking you to participate in homosexuality. They aren't asking you to go to bed with them
They are asking to bake a cake or do a job you make available to the rest of the public. When you refuse to accommodate them because of their race or sexuality you are participating in intolerance. Or better word is oppression.
People have used religious rights arguments for slavery, segregation, and opposing mixed marriages. All of which can be reasonably agreed upon as acts of intolerance.