"ride a bus" and "go to school" are not usually the equivalent of "eating at a restaurant" or "working for a company"- in many countries, bus systems and schools are often provided by the government, with tax payer subsidies- and bus systems are often officially monopolies. A Libertarian/Classical Liberal could easily argue that discrimination in such services should be illegal, and that while unethical and deplorable, discrimination by a private individual or business should not be illegal.