Except history has proven to have different outcomes than your preference. What if Mom and Pop refuse a job and it’s made public and the outcome turns out to be they receive more business in Bigotville because of thier stance. It turns out the people of the town live up to the name. A competing business faces the choice of adopting a similar policy or going under for not being supportive of bigotry.
Bigots are not always a minority that can be dealt with through boycotting. If the majority supports bigotry then boycotting will not fix the problem. It can make it worse.