I mean, from a behavioral background it makes sense. Young single men are the ones usually starting stupid shit in our culture as well, for that matter. Being part of a couple tends to drain away some of that need to prove yourself, helps steady emotions, cultural norms about monogamy are strong enough to counter most of the violence that occurs out of jealousy, or restrain it to those individuals(so maybe it just gets translated into domestic abuse, now that I think about it. Fuck, that's a catch-22 for you.), and testosterone rage plus culture shock of 'why are these women less clad than the prostitutes in [neighboring city]?' and of course, media pressure about western culture being racist confirming that yes, this is indeed society shunning you, not just the actions of a few dipshits who decided to smash up your mailbox and key racial slurs into your door, which your landlord now wants you to pay to fix.
The average person is not a terrorist. The average person is not a rapist or a murderer. But the way the genetic, cultural, political, social, and individual (if that last makes any sense? it's hard to convey what I'm trying to say here) system combined is set up, means that if you want damage control measures, and to do the most good for the most people, allowing in families, the elderly, children, and women is probably the way to do it. I'd put priorities on families first, since they need fewer rooms for more people and are more likely to be stable, children and elderly second, young single women third.
Would it be perfect? No, because this is about trends. Nobody notices the terrorist attacks that don't happen. Nobody notices the man who, upon the last straw being placed upon the camel's back, chooses to vent about it to his social worker before he goes searching for articles about why coming to the West was so stupid. But it would help, and it wouldn't result in us complaining about a court of Human Rights, or talking about how we shouldn't let Muslims in, just those other ethnicities and religious groups. I'm all for letting them in, mind, I just don't see why that serves as justification to keep Muslims out.
Mind, I still want to stomp on ISIS with a big boot labeled "Tanks 'n Shit', and smash it again for good measure every time it starts to rise up in lich-like stasis, but you know. That's apparently out of the question. Velvet glove and an iron fist put together usually work better than apart. >_>