From previous bits, a lot of the problem is from the fact that it varies, as soon as the red in charge changes, there can be new standards for "keeping the whites in their place" so on one end you have people like the red that OL told about the guardian programing in the main story, on the other you have the leaders of the cities that went dark, because all the whites rose up as soon as they had something to rally around, plus reason to question instinctive respect for reds. remember that when M'gan explained martian racism, she still felt reluctant to actually be angry at reds, she was still upset at green bigots though, so this violent uprising is only possible because the removal of the programing, or even just knowledge of how their minds are being affected, lets them look more objectively at how the bigots among the Red leadership are the problem, which is probably why we haven't heard of any mass executions of greens.
Edit- To the point, the main issue at this point is not just the racist but how it is intrinsically tied to political power, and how that political power is unchecked with regards to racist uses of said power, there are no protections for whites that can't be removed or ignored, barring the limits on certain crimes on a planet of telepaths that aren't all irredimable monsters
But to answer the oppression was probably never to rape at will (Malekith is an example of how rare that sort of crime is on mars), and the nature of a telepathic society probably limited government neglect as well, hard for police to plausibly avoid dealing with crimes against minorities when everyone involved is a telepath- but on the flip side, the more social and emotional oppression could probably be unimaginably worse, police "escorting riffaf" away from the nice parts of town, or just the general attitude trickling down from their leadership being litterally palpable- Imagine going about your day and not just knowing that people think you are less of a person than them for your skin color, but feeling it, like everyone just outright says racial slurs to your face aprapo of nothing as you walk down the street.
Now that we know that Karmang's attempt to get Marts civilized backfired and lead to the current situation, I can;t help but wonder how Martian society would have shaken out without his help, and what the guardians planned for or expected. Maybe without Karmang the less organized groups would have struggled more, but ended up better off, as the the programed instincts would eventually backed up by groups playing into the roles over time (the reds get a lot of milage out of claiming Karmang was red, if they actually had historic red leaders arise not only would that have more value, but lead to greater ability in red leaders decending and leaning from them), maybe it would have been worse, with whites outright enslaved in the begining (considering how deep the programing is it is worryingly possible that the whites could have beleived that being a slave was their place in life if things started out badly). Also if every martian has the programing removed, what will be the socially acceptable color for the general public, I see whites keeping their color, and teaching their children to do so as a pride thing, but reds would likely become reviled, or limited to the most egotitcial or apathetic, and I could see greens pick either or just enjoy how being in the middle makes keeping the color they are used to reasonable. Then again I wonder what would the biologically most comfortable adn thus likely their natural default? It likely wouldn't even be one of the three but something else like grey
