So you can refuse customers or not?
You can refuse customers only if doing so does not violate state and local public accommodations laws and anti-discrimination laws. The left has greatly increased the number of such laws, and uses them to target members of disfavored groups, particularly Christians. It would go a long way toward solving the problem if all states would repeal their public accommodations laws relating to sexual orientation and gender identity. Wikipedia used to have a page showing which states had which public accommodations laws, but I can't find it now.
Use the money by selling a product to gays to fund conservative causes..... They can’t sue you, and can’t say you discriminated against them.