Thank you! I am going to run with this question because I am also working with discrimination in one of my projects.
Check the Microaggressions blog to get a feel for the scope of microaggression, and think on instances you yourself may have faced. Depending on how fantastic your setting is, the kinds of microaggression your characters come into contact with may look very different from what you are familiar with. Maybe give Microaggression in Fiction a read as well.
Creating your own system of discrimination and intolerance, especially one rooted in a fictional construct, is going to require serious worldbuilding. Intolerance and prejudice involve treating a given group of people worse than others for arbitrary reasons, and will involve a lot more than just microaggressions. Put extremely broadly, there has to be some sort of widely spread and internalized, possibly institutionalized thought process that somehow benefits group A while disadvantaging group B in order for larger-scale intolerance to happen. This can extend into law and government in addition to being a held belief by your differing classes. Intolerance might be driven by such (generalized) things as:
- Self-interest (disadvantaging one to benefit one)
- Self-esteem (putting others down to make oneself feel better)
- Hierarchical ideals (favoring high-status groups purely because they are high-status)
- Fear or dislike of people who are different for any number of reasons (perhaps feeding into a group instinct of discriminating against an outsider to make the group stronger)
- Propagandist/brainwash/similar setup that feeds into any of these (touting one group as inherently better than another, perpetuating harmful lies and stereotypes about one group that start to be taken as truth, etc.).
Writing about intolerance and prejudicial discrimination is going to be a lot deeper and a lot more complex than just working out microaggressions. Consider why this happens in your world, including but by no means limited to things like:
- Blame as a method of enforcing cooperation and discouraging dissension against oppressors. If people of a given group are constantly being arrested/disciplined/etc., people may chalk it up to a fundamental attribution error, maybe causing an effect similar to “resetting” the morality of a world by coding “bad behavior” as “group B” in the minds of the populace.
- Going further, the idea may perpetuate itself by confirmation bias. If the given group is constantly (and publicly) treated with prejudice and given discriminatory treatment, and if enough people begin to connect “group B” with “bad” as a result, they may begin to favor other people and groups that agree with this idea and disfavor people who disagree.
- Maintaining status quo. If oppressors have a reason to keep a given group where they are socially/economically/geographically/similar, spreading intolerance via whatever conduit they have at their disposal in order to maintain the current state of affairs benefits them and disadvantages the given group.
Give all these things some consideration as you continue your research and writing.