If a company were to look for candidates on a site that only accepted rich white men, there would rightfully be outrage. Narrowing the hiring pool to a certain group based on race and sex _is_ discriminatory, and your website is facilitating such blatant discrimination.

Edit: to expand on this, to discriminate is to discern a difference in something. You are explicitly discriminating based on gender and national origin. This part is inarguable. Whether it's right or not is another question.