One, the founding fathers would have scoffed at the idea that any government could force slave owners to free slaves against their will. I know you couldn't care less about the framers, but I just thought I'd mention that fact.
Two, why oh why oh why would anyone not want to serve gay customers at a flower shop? Decent, respectful, tolerant people don't do that to others. That's just common courtesy and tolerance for the beliefs of others.
Sound familiar?
One, you know nothing about our history. Slavery was always contentious. John Adams (the second president) was always against it, as were many others.
Two, it's been talked about at length, including here. You are unaware on that score as well.
Three, what about other people's feelings? Just go someplace else, everyone will be happy.