I'm not sure why so many are against this. Businesses and business owners/managers should have the right to refuse services or products to people if they go against their beliefs. The main issue here: sexual orientation. They should not be forced to provide service to them. They have freedom of religion and it's their business, so they should have the right to refuse service.
Discrimination towards anyone in a public place is a violation of civil rights. A business that isn't involved with a religion is open to the public because the business is not a religiously oriented organization therefore you cannot justify discrimination on the basis of religion. I however do believe that churches should not have to do gay marriage because the churches are religious places and the government forcing them to clash with their religiously would be a violation of the first amendment (freedom of religion).
Although I agree that gays have rights--like everyone else--I do not agree with giving them the right to take away religious freedom just because people disagree with them. Businesses want the freedom to deny service for them. Taking away this law that gives religious freedom is like forcing them to agree, accept, and embrace their lifestyles and their values.
I agree that people should not have their first amendment right of freedom of religion stripped away from them. This is why I mentioned that churches should not have to do gay marriages if they do not support it however, businesses are open to the public (which does include gays) besides someone's personal beliefs. It is considered extremely unprofessional to voice personal opinions that can offend others in a public area. This is why you cannot simply refuses service gay customers.
Perhaps in public businesses (restaurants, theaters, etc.) that applies. However if bussinesses are asked to make something supporting the gay cause (bakery making LGBT marriage cake, business making signs supporting gays, copier making LGBT fliers, etc.) Those should be able to refuse those kind of services to them because of their beliefs. If a business that makes products is asked to make something they don't support, or that go against their beliefs, they should be able to refuse. It was a pleasure debating with you by the way.
The pleasure has been mine and I respect your position. On the other hand if a bakery is asked to to make a wedding cake for a LGBT wedding the bakery is a public business which is doing services for anyone as long as they are compensated for their services. You must make a fine line between business and personal opinions. There is a certain decorum you must present as a professional and that means you just do your job and suppress your own feeling so that they do not interfere with your work.