Discrimination is the unjust or prejudicial treatments of people based on different characteristics of people, most commonly on the grounds of race, age, sex, sexual preference etc.
It is unjust because none of these characteristics are relevant to how people should be treated, or how well somebody can perform in the workplace.
Unfortunately, many mainstream religions discriminate openly, and modern society has become tardy in analysing discriminatory religious views and condemning them.
The Submission to the Australian Attorney-General's Department on the Consolidation of Commonwealth Anti-Discrimination Laws makes a compellling case against invidiious discrimination. As there is no moral distinction between discrimination on characteristics including sex, religion, sexual preference or race, if one is ethically wrong, then they all are wrong.