Do you have a good source on that? Every school book and college book I've ever checked, plus Encarta and Wikipedia, explicitly state that it is one continent.
A continent could be a single landmass or a part of a very large landmass, as in the case of Asia or Europe. Due to this, the number of continents varies; up to seven or as few as four geographical regions are commonly regarded as continents.
I'm willing to excuse their faults. They mostly do it out of the consequences of colonialism and cultural appropriation. That's just as much as saying they do it because of the barrel of a gun.
That said most proposals I've seen on the subject are... silly or unwirldy. I'm not gonna call people from the US "estadounidense" (looooong) or "USAmerican" (uppercases) unless they tell me they're OK with it. I'd be fine with otherwise distinguising eg.: something like "American" vs "Américan", since English has been fine with diacritics for a good while of centuries already (née, naïve, blasé, etc).