There is a hole in the Pension argument, immigration would have to increase several fold to plug the gap. Overall migration is not a drain on the host country.
Blaming the problems on the tree hugging multikult left enrichers is ignorance at its highest, it was the right wing governments (1950s+60s) which started the whole thing and Left wing Governments(mid to late1970s) that recognised the problems and tried to curtail the migration. The second wave is a direct result of Right wing economic policy of opening up markets and so on.
The social freedoms that Europeans have were hard won and its illogical to curtail our way of life in order to save it.
In most of Western Europe Political/religious forces are anathema to most people, even religious folk, save for a few individual areas (Abortion being the most obvious), however, that is what many Muslims have done. We have insular Muslim communities that refuse to integrate.
Immigration is often treated as one thing - as if New Zealand computer experts, American bankers and Polish plumbers fell into the same category as villagers from Pakistani Kashmir. Trouble in immigrant communities and between them and indigenous communities must be understood in terms of alienation and exclusion
as well as in terms of Muslim aggression. The key is recognising the peasant mentality among many poor Muslims. Women don’t work, marry young and have larger families. All this leads to a vicious circle where educational skills are not there to pass on (Exactly the same applies to some indigenous people). Many other Muslims integrate successfully.
Naturally such ghettos lead to tension.
Race hate legislation has forced a change in some, its easier to denigrate people in terms of faith rather than race. This neo con idea that Europe has lost its sense of purpose is easier to understand and promote if you categorise people by faith rather than colour. Muslim immigrants are being treated as the new red peril.
Al-Qaeda is a modern phenomenon projecting a privatised form of organised violence on the world is pure globalisation and also impossible without globalisation, the idea that self immolation can change the world is the same view as 19th century anarchists, not the medieval world. None of their leadership were at Islamic school nor were the 9/11 bombers or the7/7 bombers indeed many were western educated living a secular life.
What you now have is right wingers creating a problem in migration and providing no solution. The reason we cant reverse the situation is economic. Resurrecting massive protectionism will see much more social upheaval than that predicted by the scaremongers.