Throughout human history, cultures, tribes, and religions were removed by those more powerful. It isn't a new concept. Islamic empires have had expansionist policies, displaced many tribes and clans, and, for political, family, and other reasons, the empire saw fit.
As a secular nation, the Americans have democracy and capitalism to offer the world, which, by their very nature, have done more good than harm. You and I enjoy the very computers and technology we have today because of the West and its research and development.
There is always an exchange in a relationship, if the West gives you the right to live and abid by it's laws; you must work, pay taxes, and take part in civic duties, it's your adopted home and you take an oat; and if the oat goes aganist one's beliefs he's free to move about the world, as Allah himself said, "my world is vast."
Assimilation happens everywhere; you take the good and remove the bad. No one is taking a gun to your head and asking you not follow your beliefs. But the same can't be said in our part of the world.