That's false. There are two major problems with Mercury:
1). Being the planet closest to the sun, it's not surprising that the temperature on the lighted side is excessive and hard to deal with. AND, since the planet does rotate, any place we might choose to settle there would be illuminated by the sun sooner or later.
2). Mercury is so deep inside the solar system that it takes huge, expensive amounts of energy for us to send anything there ... about as much as it takes to send a spacecraft outward to Saturn !