No, the vast majority of what you call "slaves" are from the poorest countries across SE Asia i.e. The Philippines, Indonesia, Bangladesh, etc. They're subjected to harsh conditions, but the thing that separates them from being "slaves" is that:
1. They willingly went to Dubai
2. They're paid for their work, though far less than they were promised and far less than any human should get for the amount of work they do.
3. If they stop working, they're deported back to their home country.
While definitely terrible conditions, they're not slaves in any way, shape, or form.