This means that just because other people can get away with insisting and socially enforcing that what they are doing is Right and that you do not have the right to be angry about it.
There is no ‘fair’, no ‘justice’, except to the extent that I or other people who share similar preferences make it so. Other people may get away with insisting that what they are doing is Right, with the implication that you do not have grounds to be angry. They may be able to socially enforce the suppression of anger at their actions with clever reframing or outright force. But you need never subject your own feelings to their demands. You don’t need permission to be angry.
Heads up—I failed to parse
That makes no sense. Edited to: