It's just a political game. Any revolution offers opportunity for ambitious clinical psychopaths to exploit the chaos and cement their character in future history books (although there are many ways to achieve this). One way to bring about such a 'revolution' is to incentivize the billions from the developing world to gradually overflow into Western cultures and give them a political platform from which they can 'punch up' at their 'oppressors'.(Original post by jeremy1988)
Muslims are today's noble savages, and thus above reproach. Everything they do is excused and protected as part of their culture. Sadly, this was applied to even cannibals and tribes guilty of human sacrifice back in the day, so this madness knows no bounds. It's just that in the old days, average people were too smart to listen to that form of left-wing thought seriously. Now, there are enough of these starry-eyed, noble savage praising romantics running around that we have to worry what they think.
Putting them in a cocoon of the 'noble savage' is one such platform.They do outnumber the populations of the West after all, and produce kids at far higher rates. If you get on the right side of these people and wait a few decades, you'll probably start winning elections with their votes.
I'm not implying that every person who supports mass migration has these ambitions, but I know some certainly do, even if they're a minority.
100s of personal statements examples here