"set that against a cultural immigration that has only taken place in the last 20-30 years and which in places seeks to not just dominate but replace .. educational systems, political systems, culture, philosophy, every aspect of life as it is knowm ... with, in many cases repressive, ideology..."

I've not seen a single example of any immigrant group to the west trying to replace the culture to which they immigrate, let alone Islam. They, of course, maintain their own cultural identity and religion, especially for a time, but that's pretty standard. Eventually some of these cultural attributes become integrated into and accepted by society at large, just as the immigrant groups eventually adopt new customs. Food, music, holiday traditions, etc.

The US has a lot of experience with immigrant waves. Each wave of immigrants has been reviled and persecuted as being less than human -- the Irish, Italians, Chinese, Japanese, Mexican and Central Americans, and so forth. All left in their wake an America much richer for their contributions. It shouldn't be surprising that immigrants from the middle east are treated with the same contempt, but you'd have thought we'd have learned our lesson by now.