Valentines Day, Arbor Day, April Fools Day and Mother's Day are not even highlighted on the calendar that opens the short. Also, Easter is shown on the calendar as April 9th, but is later cited as March 24th (the correct date). Thanksgiving is shown on the calendar as November 30th, but was actually designated as November 21st by President Roosevelt (hence the political dig).
For Washington's Birthday, George's father speaks in an "Old English" dialect. By the 18th Century, English had evolved into, for the most part, what is spoken now. Thou had fallen by the wayside in favor of "you".