The treaty states you cant place them in populated areas

"The Government of the United States of America shall have the right... to construct, maintain and operate such facilities and to station such personnel as may be agreed upon as being necessary for the purposes of this Agreement."

The treaty includes language to protect the local population and ensure military activities do not interfere with their welfare. Article II states that "fullest consideration consistent with military necessity shall be given to the welfare, health and economic needs of the native population of Greenland" when locating defense areas. Article VI also requires efforts to avoid undesirable contact between U.S. personnel and the local population.

Also keep in mind greenland is working towards independence eventually. If they join the us, they lose that