There are certain reasons Tony, I think these are few of those reasons:

1. Some cannot leave Qatar because of the better salary that they can get here than home.
2, Some cannot leave because their employer/s wouldn't allow them to or even threatened to cancel their visa. (which will hold your chances to get a better company)
3. Some cannot leave because their passport is in their employer's care.
4. Some cannot leave despite the fact that they were mistreated here in Qatar, they're still thinking about the remittance that they could make for their family.
5. Some cannot leave even though they are dying to but their employer/s withheld their salary for 4 or 5 months and cannot afford to buy his/her own ticket way back home.

And all they can do is.... sigh, complain, pray, and wait for a miracle to happen.

Easy to say... if you dont like it, leave! Different complaints, different circumstances.

And oh! by the way, I hate the trend of their clothes here,,,, does that makes me wanna leave Qatar?