Noah Webster early on says this is not the king's English, this is not the language of the nobilities; it's the language of the trapper and the farmer and the tradesman. So early on it was almost a patriotic thing. Thomas Jefferson to this day has 114 words credited to him in the Oxford English Dictionary. The most famous, and the one that drove the British nuts, and even up through Fowlers Modern English Usage, which came out in the middle of the 20th century, still bothered by it, was 'belittle.'
It bothered the British deeply that an American could just come up with a word like this. They thought it was their language and we got to use it. We weren't supposed to tinker with it.
And here's one of the more famous (alleged - he apparently never said the word) presidential contributions to the English language: