What was the main aim of the northwest ordinance of 1787?

The Northwest Ordinance (officially An Ordinance for the Government of the Territory of the United States, North-West of the River Ohio) was unanimously passed on July 13, 1787. The primary effect of the decree was the creation of the Northwest Territory as the first organized territory of the United States outside the southern Great Lakes, north and west of the Ohio River, and in the east of the Mississippi River. On August 1789, the United States Congress approved the decree with slight modifications to the constitution.

since most of current immigration into the u.s., both legal and illegal, is coming from latin america. it would be very difficult to imagine or rationalize a country my fellow citizens are trying desperately to flee into, would pose a threat to my prosperity or freedom. since the u.s. has a long history of intervention, but no record of permanent occupation, i would not feel oppression is the main objective.  

the largest free trade nation, along with the largest gdp in the world wanting to expand it's economic policy on us, and including us, could only be positive. the u.s. government has no interest in, or way of simply forcing american culture on us. and has no track record of it. other nations that adopted american social culture, or "americanization" did so voluntarily, mainly through the choice of allowing american businesses and u.s. citizens to come into their nations, as free operatives.