A person in a position of authority can deflect criticism by merely stating, "Those are the rules." This can be used as a silencing tactic to defend unjust or discriminating rules. It may also be an appeal to tradition, one of many logical fallacies.
Standing firm on an unjust rule places the Second shift burden on the marginalized party to either fight the rule, and use up time and resources, or remain marginalized. As rule-followers are generally seen as being good in society, rule-challengers risk being labeled trouble-makers or anarchists, particularly if they are othered.
The person in power can claim that he or she is merely following orders from above. Other times, the person in power may simply stand firm because they stated their rule once and don't wish to be corrected.
Society generally frowns upon obvious power-abusers. Mere rule enforcers, not so. It is the assumption of neutrality on rules that makes systemic oppression difficult to resist.
Backlash against rule-challengers can be subtle, such as the tightening of existing rules. Existing rules can also be made to be broken easily through carelessness and not intent, with severe consequences. Excessive monitoring and further othering may also follow, similar to closely following a non-white person through a store.