"a lawyer is a lawyer, he is either a social engineer or a parasite on society"
One reason it was a health threat is it caused teeth to become ground down which would then lead to infections. The same was true with their eyes and lungs, sand would be blown into their eyes or inhaled into their lungs and then could cause infections.
Answer: Alexander spread Greek culture throughout the Persian Empire, including parts of Asia and Africa. Alexander respected the local cultures he conquered, and allowed their customs to continue. Alexander himself embraced local customs, wearing Persian clothes and marrying Persian women.
It was the term European colonizers used to justify their colonization in America. They believed it was their god given right to expand West.