You are misunderstanding what the GP comment said. The reality is that landlords/employers can and do discriminate based on race, religion, age, etc all the time. They simply just can't say it out loud, that's the illegal part.
I find that Asian people tend to be pretty open about this stuff, whereas in the west it's taboo. Don't think that anyone would be foolish enough to try arguing that there's no silent discrimination occurring in the US.
