Answer:
Because they are Absolute ruler who used his or her power to bring about political and social change. Despot means "absolute ruler."
Step-by-step explanation:
The 'enlightement' introduced the idea that the kings should not be the one that has the highest power in a country. It should be the law.
Several rulers in 18th century (including the founding fathers) use their power as a ruler to instill law as the highest power in the country. The founding fathers did this by establishing the constitution and representative democracy. The constitution made government officials became a subject to the same law as the citizen. Representative democracy give the citizens with the ability to overthrew the rulers in case those rulers fail to fulfill their duty.