This is a statement of fact, and easily supported by Islamic texts. The "liberal" pretense that this is not so is idiotic and blatantly uninformed.
Islam seeks "submission" of all to it.
It is also a problem for Islamists, as it is a similar problem for corrupt politicians as for Leftists. All agree that someone should "rule," but then they fight one another to be the "ruler." This has been the history of conflict between sects in Islam, as between socialists of various flavors, and of course, for the corrupt politicians, there is never any honor among thieves.
Birthrate is compelling data.
Muslim birthrates far exceed all others. They WILL achieve these goals.