The fact that an employer does pay or reimburse membership fees or other expenses associated with participation by its employees in an exclusionary private organization establishes prima facie that such participation confers an employment advantage or constitutes or results in discrimination in a term, privilege or condition of employment on the basis of race, color, sex, sexual orientation, religion, national origin or ancestry. The employer shall have the opportunity of demonstrating to the Commission that such an employment advantage or discrimination does not exist.