Question

Why did herbert spencer's theories on social darwinism appeal to imperialist

Answer 1

Theories on social darwinism appealed to imperialist in general because imperialists could claim (falsely) that Darwin's "Survival of the fittest" conclusion meant that it was only natural for the "stronger" states to take over the "weaker" states--meaning there was no moral issue. 

Answer 2

Because Herbert Spencer stated that the strongest civilizations would conquer the weak