Is Facebook allowing ads that discriminate against ethnicity?

Facebook is allegedly allowing advertisers to post adverts on their platform that can exclude users based on their ethnic origin. 
The social media giant's ad platform allows advertisers to target specific user groups based on information provided by Facebook users, however a report by non-profit investigative journalism group ProPublica said that the system is being used to exclude specific groups it calls 'Ethnic Affinities,' that include black, Hispanic, Asian Am