It was Richard Nixon who called it "Presidents' Day" by which he probably meant to include Washington and Lincoln, but the ignoramuses in the media turned it into a holiday in honor of all the Presidents (except for Washington's predecessors who were "Presidents of the United States in Congress Assembled" and of course Jefferson Davis).
Lincoln's birthday was never a federal holiday.
Yes, all true, though I refuse to call some random Monday in February “Washington’s Birthday.” And find 1 in 50 Americans who don’t call that phony event “Presidents Day.”