As if America being all white would change anything, it has been the Great Satan since 1933. Even before then it had many dystopic features and hostility to whites, largely due to jewish influence but also just because bourgeois elites are subhuman. Since 1933 it has been a steady trajectory of more and more anti-whiteness at the behest of the jews controlling it.

In short, the reason isn't abstract it's concrete: America is the empire enslaving and genociding white people, it's in our interests for it to be destroyed.