However, strictly speaking, nothing in Powell's speech is namely about integration but immigration only.
Then you need to reread it.
The other dangerous delusion from which those who are wilfully or otherwise blind to realities suffer, is summed up in the word "integration." To be integrated into a population means to become for all practical purposes indistinguishable from its other members. Now, at all times, where there are marked physical differences, especially of colour, integration is difficult though, over a period, not impossible. There are among the Commonwealth immigrants who have come to live here in the last fifteen years or so, many thousands whose wish and purpose is to be integrated and whose every thought and endeavour is bent in that direction.
OK. You said "nothing in Powell's speech is namely about integration but immigration only" I am just pointing out your error. ::)
I think you misunderstand my request : Just asking for some evidences about your following statement : (...) "also about non-productive immigrants who come to the nation to get free stuff like health care." 😛