The problem is, the only people this is going to help are the very terrorist organizations they claim they are trying to stop. As Wikipedia says,
The el-Bakraoui brothers were known to the Belgian authorities. Unlike other radicalised ISIL adherents, who started with small criminal offences, the two men had a criminal history of more severe crimes. Khalid (born 12 January 1989 in Brussels) was convicted in 2011 for a series of car-jackings and was released from prison in early 2016 after serving most of his sentence. In January 2010, Ibrahim el-Bakraoui (born 9 October 1986 in Brussels) was involved in the attempted robbery of a currency exchange office, where he shot at police with a Kalashnikov rifle.
Meaning that cutting off refugees from Europe and closing down the borders is not going to help anybody. This war is not a war of invasion by people on the ground, this is an ideological war where the weapon is the internet, and the war is primarily in words. It is not exclusively in words of course, given the conflict in Syria and Iraq, but the weapon of the Wahabbis is the weapon of trying to convince people that not all people are important, freedom of speech is blasphemy, and democracy is against the word of Allah. This of course is wrong, if you look at the vast majority of Muslims around the world who want to have peace (though the Wahabbis would probably claim that since they are not of their perverse movement) and that Islam is very compatible with democracy in multiple countries (Turkey, Lebanon, Malaysia, Singapore, Indonesia, Bangladesh, and India among others) where over half a million Muslims live in these countries, more than 1/3 of all Muslims worldwide. Most Muslims live in countries like Iran and Egypt which have elections but are not as democratic as the others I mentioned. Only a minority of Muslims in the world live in countries like Saudi Arabia and Qatar which are undemocratic. The calls for closing the border are racist and based off a gross misinterpretation of reality.
Where do we go from here? We need to continue the ideological fight against Wahabbism around the world. We need to grow people to people connections and trade with Muslim majority countries in resources far beyond oil. There is a very unfortunate correlation between Muslim majority countries having a large amount of oil which is demonstrated to be toxic to the economy and political climate of countries given the nature of the market. Middle Eastern countries are where extremism is bred more than any other part of the world, and the dictators of these countries need to fall. The biggest thing we can do now to end this is to reduce our consumption of oil which will starve the dictators of their source of revenue. They will be forced to diversify their economies which will lead to a dispersion of income to all people in the economy. Women will have more jobs available, and opportunity will expand throughout the economy. This will translate into less extremism because people will have futures, and with fewer people living in poverty this is going to reduce the number of people going to terrorist organizations because they will have more to lose. Other countries where terrorism comes from are all poor countries, and by reducing their government's dependence on foreign oil which gives them money to fund their militaries keeping the people from protesting. This is the way to fight terrorism, by cutting off the causes of what drives people to such extreme measures, and by opening up the channels of communication we can have understanding between peoples of the world. We need to build a world with more love and listening as opposed to hatred and closed mindedness.
Our world is one world. What touches one affects us all. The seas that wash us round about. The clouds that cover us. The rains that fall.
From Singing the Living Tradition
Closing the borders on the other hand is the opposite of what we need to do and is only going to make terrorism grow. It is the denial of that reality that we are all part of this world, and our actions affect one another.
http://time.com/3679537/rich-nation-poor-people-saudi-arabia/
http://www.bbc.com/news/world-europe-35869254