To not discriminate is to not make value judgements, I'd rather people make those judgments out in the open. Laws against racial discrimination just brings the behavior underground.

For example, the Christian cake maker. Whether you like it or not, they had a right to not make a cake for the LGBTQAII+ couple getting married. Just as customers can discriminate, so can suppliers.

Is it good business practice? I don't know, but its the shop owner's right.