'Mass immigration of Muslims - or any foreign ethnicity - is a threat to the integrity of European culture, customs, economy, and security, for the EXACT same reason that a mass immigration of white people would be a threat to Iran, say, or Lebanon. Etc.' - I don't think this is right because of differences in relative wealth. As I understand it most of the refugees arriving in Europe are starting from scratch at the bottom of the social scale (even if it cost them thousands to make the crossings) whereas Europeans emigrating to 3rd world countries, even if not doing so in a direct colonising/occupying capacity, distort the local economies by bringing in the extra wealth they earned in their higher-income countries of birth (ironically itself an outcome of ongoing plunder of the 3rd world). Israel provides a good example, eg this passage from Newsinger's 'The Blood Never Dried':
'Between 1920 and 1939 the Zionists purchased more than 846,000 dunams of land, which brought the amount of Jewish-owned land to 1,496,000 dunams. While this was only 5 percent of the country’s total land area, it was a fifth of the arable land […] what this meant was that in 1935 each Jewish colonist had an average of 28.1 dunams, while each Palestinian had only 9.4 dunams. This transfer of land into Zionist hands inevitably resulted in increased poverty and landlessness for the Arab population. Moreover, with the explosion in Jewish immigration came an influx of Jewish capital that led “to an excessively high rate of inflation when agricultural wages were severely depressed”. And, of course, the Arabs were not just evicted from their land, but were also confronted by the Jewish-labour only policy of the Histadrut, the Zionist trade union movement. Employers who took on Arab workers were picketed, often violently, in an attempt to drive them out. Even when they were employed Arab workers were paid considerably less than Jewish workers. For many Arab families, the shanty slums that grew up around the towns and cities became home […] in 1935 in Haifa alone, there were 11,000 families living in these new slums.' (p.130)
Europeans aren't about to be forced into shanty towns because foreign immigrants bought up all the best land and began to dominate the economy and major national institutions, no matter what shit-stirrers like Hopkins say.
Fwiw I was surprised and suspicious of the whole 'refugees welcome' story too, but I've not seen any good analysis of that period to make my mind up about it. It never seemed be connected up to any anti-imperialist critique along the lines brooks articulates, which is why I'm not surprised at the reactionary backlash.