Is the opposite disallowed in the US? In Germany, we have plenty of housing coops and state run builders that e.g. discriminate against single (young?) men. I've tried half a dozen of these not-for-profit entities before I found one that said "we don't care who you are. If you want to live here and you can pay the rent, we're fine with it".

The "no discrimination allowed" is often just "no discrimination allowed that we don't approve of".