Is there a language called American English? In my opinion no! Why? English is the native language of England and not America. So English not spoken the way the natives of England speak is English spoken with a different accent or dialect.
If you say that everyone in the United States of America speaks American English, then everyone in India speaks Indian English and the number of Indians speaking English is more than the total population of USA. Further if you pursue this line of thought, then very soon we will have another language called Chinese English, the English spoken mainland China.
One may argue that there are spellings and pronunciation differences between American and British English, but that is no reason to change the identity of a language. The inability of the users is not the fault of the language. It’s like removing the Chinese characters from Mandarin and exclusive using the Chinese phonetic writing system Pinyin and calling it American Chinese. Now that will be the biggest joke in the world making 1.3 billion people laugh.
Each language comes with a long history and the culture of that native land. The English language was not developed in 200 years like the history of the country of America. The English language has a history that goes back more than 1000 years. So adding a new identity to a language with history and culture is disrespect to the native land of that language.
The bottom line is this: English is the native language of England and it should be spoken like the natives of England. Any other form of English is not a new language, but a variation of English and it should be referred to as ‘English with a different accent or dialect’. English spoken in America should be referred to as English with American accent like English spoken in India, which is referred to as English with an Indian accent.
Let’s not adulterate a language and own it by giving it a new identity. Learn it the way it is supposed to be used and if you cannot learn it, deal with it but don’t destroy it.