What if the tenants have had more bad experiences with male arab tenants and more good experiences with female italians? Could it be called "science" instead of "discrimination"?
Are you telling me that whole munich had arab tenants at least once in their past?
For example, why would anyone expect the same behaviour from a single black criminal drug-addict as from a married black lawyer with kids? The fact that they share the same skin-tone is the least important hint to their potential behaviour, and yet, historically, it's what people use because it's the first thing they see.