Former slaves deserved to own land, they earned. For their wages, pain and suffering, former slaves deserved to have their own territory, their own country. The land in the Louisiana Purchase was bought for $ 15,000,000. Again, if we take in consideration the average wage of the year 1742, when a person earned $500.00 a year and in 1860 there were 4,000,000 slaves .If we multiply 500 x 4,000,000 = $2,000,000,000 = 133 " Louisiana Purchase" in a single year This a rough estimate, although, it makes more than sense. Former slaves had the right to own land bigger than the Louisiana Purchase territory. Additionally the Louisiana Purchase was made in 1803, which add more reasons for former slaves to own land.

Anyway, it was not the government’s land, is the land of Native Americans' because taking by force is stealing. African Americans could have paid a fee to Native Americans for using their land. Also, Native Americans could have lived in their land. It sounds unfair for Native Americans, but it could have been a better deal.

source: Slavery-Crash Courses US History #13 ( Minute 2.36 to 2.38).