Three things are quite clear, and cannot be seriously argued: - There is a connection between the bout of terrorist attacks and Islam (not at 1-to-1 connection or direct correlation, but there is a clear connection) - Most Muslims of Europe aspire to live in peace in their country of residence, but have received unequal welcomes in those cultures (This is not the cause if the attacks, but it makes it easier to recruit for them) - The likes of the so-called IS (DAESH) do not want Islam to be welcome in Europe: the more we reject Islam, the stronger they get
There is nothing I would hate more than changing policies to suit DAESH's goals. But it turns out that being more open, welcoming and understanding of Islam is the opposite of their goal, and is better path towards a pacified Islam.
When a religion integrates positively in a society, it is less likely to want to change it. It becomes less extreme and less literal in its contents. More and more people start referring to themselves as "believing but non-practicing".
There is no reason our European cultures cannot do with Islam what we did with Christianity and Judaism: domesticate them!