The first line of the act reads:  "Prohibits the federal government from taking discriminatory action against a person on the basis that such person believes or acts in accordance with a religious belief or moral conviction that: (1) marriage is or should be recognized as the union of one man and one woman, or (2) sexual relations are properly reserved to such a marriage.".  You will have to decide if that is just or unjust yourself.  For me, it is unjust, as it allows one to discriminate against another based on religious belief.  It would allow a so-called "Christian" to refuse service to anyone who doesn't meet their criteria.