Just no. The typical Daesh Volunteer is largely a muslim mirror to Incels, Red Pillers and more extreme alt-righters. Young, uneducated, poor men who feel that society has left them behind. They have no interest (or ability, probably) for integrating into society and are easily picked up by radicalizing elements on the internet, whether that is a jihadist facebook page or braincels. The difference is that the Daesh volunteer will see that society shuns him because of his religion, the incel/red piller/alt righter will see that society hates him because of his gender or color of his skin. These are very, very similar in radicalizing young men into groups were violence against contemporary western society is glorified. The difference was that Daesh provided a direct route to do that instantly (through killing Syrians and Kurds, ironically) while alt righters are still "preparing".
Because the average muslim is no harder to integrate then any other emigrant. In Sweden we have the Bosnians who came as refugees in the 90's who's children are, statistically, among the most successful and well integrated in Swedish society today. Before them we had the Iranians in the 70's and 80's, who are perfectly naturalized as Swedes today. France has an absolutely massive muslim minority from the old colonies who are muslims but are also French to the very bone. England has a similar but smaller minority. In Yugoslavia the Bosnians, Montenegrians and Kosovo-Albanians were all well integrated prior to Milosevic using ethnicity to rally the Serbian minority against them.
There's absolutely nothing about muslims that makes them uniquely impossible to integrate. What we are seeing in Europe right now is simply the product of two decades of poor integration and decreasing societal cohesion on all levels (partly fueled by Islamophobic right wing parties) causing social problems on many levels. Since immigrants are usually the poorest and least socially mobile they are also the first to end up in situations were desperation breeds crime, radicalization and segregation from mainstream society. This is nothing new, it is happening all over America all the time with "white trash", it has happened in every European country in the 19th century when hobos, vagrants and similar groups were largely disconnected from society at large.
I've met way too many well-integrated muslims to believe for a second that they can not be integrated, nor is that position supported by the historical integration of muslim minorities into European societies. That's just Islamophobic bullshit othering meant to cause an even greater divide to them, instead of allowing them to assimilate into society at their own rate and in their own way.