The Turkish guest workers In Germany did not go around stabbing Germans. They were polite. And grateful to be there.
The first wave of immigrants generally are appreciative of their hosts.
The problem starts with the offspring, and subsequent generations, who don’t appreciate the conditions their parents fled, and are more prone to radicalization.
And some of them were engaged in kidnapping German girls and smuggling them back to Turkey. I remember several stories about that in the Frankfurt area during my 7 years there.