This Land Is Your Land was written by legendary American folk singer Woody Guthrie in 1940, the year in which America was transitioning from the Great Depression and the New Deal to preparation for World War II, which was already raging in Europe. It was written in response to Irving Berlin's extremely popular- but oppressively cloying and jingoistic- God Bless America. Early versions of the song were criticized by bigoted, ignorant morons as endorsements of Communism (and therefore, of course, Un-American and Wrong.) This Land Is Your Land was not released until 1945, at the end of the conflict with Germany and Japan and the beginning of the conflict with the Communist World.
The song originally included the phrase "God blessed this land for you and me," but Guthrie didn't want to mock Berlin's song and he didn't want to exclude non-believers, so he changed it to "This land was made for you and me," It also includes verses mocking the idea of private property and walls designed to keep people away, and actually questioned the direction of a country which claimed to be an island of freedom in a world of slavery in a pompous, clueless, Disney-ish "America Love It Or Leave It" kind of way.* These were scary concepts in the 1940s and are scary concepts now, because when it comes to shallow and paranoid, nobody beats Americans.
And when it comes to using classic songs to sell stuff, again, nobody beats Americans. Which is why we now have the song which really ought to be the National Anthem (wouldn't this or "America" be far better choices than a song about an assault on a fort during a war nobody remembers?) being used to sell jackets and backpacks. Ugh.