It shall be unlawful to deny any person access to or membership or participation in any multiple-listing service, real estate brokers' organization or other service, organization or facility relating to the business of selling, exchanging or renting dwellings, or to discriminate against the person in the terms or conditions of such access, membership, or participation, on account of race, color, national origin, religion, creed, sex, marital status, familial status, source of income, age, sexual orientation, gender identity or disability.