Slave owners when slavery was common doesnt make one a racist.
People who owned "chattel" slaves were racists. They believed people of other races (black, Chinese, sometimes Irish) could be owned, but others could not.
No person should sell their stock in Starbucks because of this. If you own stock in Starbucks, you didn't care about their social policy positions when you bought it, and they haven't changed them recently.
This person is just seeking publicity. He should go get his photo taken in front of Chik Fil A.
So if you are a Christian caterer, bed and breakfast, etc. too bad. You will be forced to provide services to a gay wedding. You will be made to by the power of the state. Thats where we are headed. If the state has the power to change the definition of an institution it did not create, the state can compel your services to that institution.
I'm so old I can remember when people said this about hotels allowing black people and Asians. Time change, countries change.