These people are incompatible with western society
Modernism, especially in the incarnation of neoliberalism is all about the mass movement of humanity. Capitalism and communism both share a mania for moving people around like containers in a dockyard with no concern for what happens to them.
What's being done to migrants in Africa and the Middle East is horribly cruel to them. They're being told they need to go to Europe and once they arrive they find they serve no purpose and cannot fit in and have no hope at any kind of dignified life.... so they lash out.
And the slavers known as human traffickers (which includes the NGOs picking up their boats in the Mediterranean) keep the flow up because they're making money and the feckless Europeans say 'nothing can be done....' and things like welfare states and human dignity are being lost.
Those who support the current European slave trade are no better than those who supported the Arab or Atlantic Slave Trades.