It may be a frustrating experience and I hope you eventually find a suitable accommodation for your family, but you must understand people have a right to choose. I cannot speak for the agents but you have to look past people's preferences and not take it personally. There are 'families only' ads, 'Muslims only', 'bachelors only', 'westerners only', 'south Indians only' 'Arabs only' etc. It is something that is common here even with job vacancies, you just have to deal with it whether you consider it unfair & discriminatory.