This assimilation-integration thing must be embedded in a Germany context. The fall-back position of German conservatives after the abandonment of the guest worker fantasy was that immigrants indeed have to choose between identities: be a German, or be a Turk. In their view, there is no such thing as having both; someone claiming a German identity while not ready to let loose of the Turkish one is a 100% Turk in disguise to get the benefits of German citizenship. Or, at least, that's the ideology behind their categorical rejection of double citizenship a few years earlier, and later expressed views on education and 'leading culture' followed from that. This is what Erdogan reacted to.

_{*Lunatic*, n.
One whose delusions are out of fashion.}