Who were the fast talking speakers that delivered short patriotic speeches at movie theaters?

Four minute men

Explanation:

The four minute men was a volunteer groups which is authorized by the government to give speech that increased people's willingness to join the army. (which is why the speech had patriotic themes)

At that time, President Wilson authorized this because He felt that United states did not have enough troops to ensure our victory on world war I.

Within 1 year, the volunteers of the four minute men have given around 7.5 million speech over 5,000 communities.