According to Kennedy, why was the time period during which this speech was given similar to that of the American Revolution?

Fighting a tyrannical foreign power

Explanation:

Assuming you mean JFK (best president of all time, absolute chad) he was likely talking about how the American people need to unite to fight the Tyranny of the USSR (very cringe and smelly, lots of dead serfs.) Also was probably talking about how it's important to value American ideals such as freedom and liberty. Likely because Communism was growing fast (also bad, no freedom and also basically the opposite of the American economy)

i think they came to washington to protest

when world war i broke out across europe in 1914, president woodrow wilson proclaimed the united states would remain neutral, and many americans supported this policy of nonintervention. however, public opinion about neutrality started to change after the sinking of the british ocean liner lusitania by a german u-boat in 1915; almost 2,000 people perished, including 128 americans. along with news of the zimmerman telegram threatening an alliance between germany and mexico, wilson asked congress for a declaration of war against germany. the u.s. officially entered the conflict on april 6, 1917.