Oh dear Rob
Basically you're saying that there is nothing that the international community and some of the most powerful corporations in the world can do to mend a bad situation, and we should all just accept exploitation and human rights violation as the unchangeable status quo.
It doesn't matter whether these workers are 'used to' these conditions, or whether neighbouring countries would do the same. What matters is that FIFA and their sponsors have the blood of hundreds of workers on their hands for failing to protect their rights, while building infrastructure for their own tournament.
No the weather can't be helped, but forcing people do to 18 hour shifts of manual labour a day in that weather, causing many to die, can be helped. The main problem is not that these workers can't leave, because if the conditions were reasonable they wouldn't want to leave.
What is it people want Qatar (the country with the highest GDP per capita in the world) to do? Stop profiteering from the exploitation of migrant workers, by providing them with reasonable labour and living standards. It's pretty simple.