Sponsor system is nothing but slavery and it is practice of dark age. Even Muslim prophet forbids any form of slavery and there is big punishment for people who promote or assist in such act in Islam. For those people who think Islam is life style of Qatari people or what government practice here (slavery) please read Islam. Islam is religion of peace, mercy and forgiving. Helping poor and needy (paying Zakat and sadkah—Islamic poor people tax). Just human right -Pay your workers before their sweat dry.
Helping other- Help other human being (needed and poor) Allah (god) will help you.
These are many.... please read Islam and follow it and fight against such cruelty, because fighting toward such cruelty is also good deed of Islam.