A lot of people ignore the cost of discrimination to the person who is discriminating. When you discriminate against someone you are eliminating the profits you would gain from doing business with them. In highly competitive markets with low profits you have limited ability to discriminate as your company will go out of business if it chooses to do so. In less competitive markets (monopolies) you are more likely to see discrimination since there is less of a cost paid by the discriminator.

There is no magic wand to end discrimination entirely, but encouraging highly competitive markets is the best way to bridge the gap.

If you want more detailed information about market discrimination, I suggest you read "Product Market Structure And Labor Market Discrimination"[0] The same principles apply to the housing market.

[0]: https://www.amazon.com/Product-Market-Structure-Labor-Discri...