You learn something new every day, or in this case a couple of things. First, right at the top of the History of Liberia page find that the whole idea worked out well:

The mortality rate of these settlers was the highest in accurately recorded human history. Of the 4,571 emigrants who arrived in Liberia between 1820 and 1843, only 1,819 survived.

So they set a record! We also find out that the progressives have already excusified all this away:

As a result, they held American cultural, religious, and social values. Like many Americans of the period, the Americo-Liberians held a firm belief in the religious superiority of Christianity, and indigenous animism and culture became systematically oppressed.

In other words, "We learned it from you, Christians. We learned it by watching you, whitey!"