Answer:
According to King Leopold, the Congolese were an inferior race/ people and needed to be treated harshly for them to understand the importance of hard work.
Step-by-step explanation:
When Europeans first began explorations in the African continent, Africa was deemed an "uncivilized" world. Thus, the need to "civilize" and change them to be 'normal' people were the work put out for the new arrivals by themselves.
In the given passage provided, King Leopold termed the people of Congo as "lazy native[s] . . . composed of cannibals". He even stressed the need for "methods which will best shake their idleness and make them realize the sanctity of work", hinting at a harsh treatment as the only means to make the native people learn. He, therefore, justifies the treatment meted out to the Congolese so as to make them learn about the sanctity and need for hard work.