"Go ye therefore, and teach all nations, baptizing them in the name of the Father, and of the Son, and of the Holy Ghost: / Teaching them to observe all things whatsoever I have commanded you: and, lo, I am with you always, even unto the end of the world. Amen."
Same goes for Christianity. Your friends going around telling people about the good news are actually being good Christians. Also, I've never heard of any Islamic people in the Western World telling others they can't be Christian. Hmmm, maybe because the Islamic people you are talking about are called FUNDAMENTALISTS (you have them in Christianity too, fyi).
And don't give us this bullshit by singling out Islam. The majority of the "problems" you would describe, if you were to actually show some examples, are created by social differences and are always the result of both sides not willing to compromise. The majority of Turks, for example, in Germany were given work permits because Germany desperately needed workers in the 70s. Their failure to integrate is a problem for both sides, on one hand, some Germans refusing to accept that these people have different histories, coming from different cultural backgrounds. Moreover, the integration programs that were put into place were not good enough to encourage people to break from there social communities, which in many ways, is defined by their religion. Yet, it is very evident that Turkish people segregated themselves in a large way in different communities. The general argument can be boiled down to: "they didn't integrate." "Well, you didn't let them." However, if this was not the case, Berlin wouldn't be the city it is today, nor would Vienna. The same goes for Arabic peoples in France, the Netherlands and many other European countries. Also, Arabs in France are also the result of French intolerance in places like Algeria, for example.
How is it not clear to you that Christians caused the same problems among different sects for centuries until Western Democratic society smoothed these tensions over to a reasonable degree.
Lastly, fuck you and your religion. Neither you, nor it is endangered by Islam. And, maybe you should risk exposure to another culture, it might actually open your eyes or at least make you realize when it would be smarter to hide your racist views from the public.