A private business owner should have full discretion in regards of who they do business with, and should never be required to make a sale or perform a service for anyone they don't want to.
If a business owner wants to be bigoted and hateful towards customers of a certain category, it's unfortunate, but that's his/her choice. Their community of customers will probably boycott their business and pressure them into either a) changing course or b) closing their doors.
Obviously essential services such as pharmacies, hospitals, etc. must be required to serve everyone, but most other businesses should not.
If you're really from Alabama you know this isn't true for large swaths of America. In many rural/Southern areas, it's more likely that churches will start boycotting bakeries that
do serve gays than any significant boycott of a bakery that refuses them.