That's the pattern we tend to see with migrants from Central and South America. The men come, work, and then bring their families.neither report indicated that 70% are young males though, in truth, it would not surprise me if this is true as young males are generally more mobile that entire families - also Syria refugee camps are likelier to accommodate families so single males escape in order to find some means of support that they cannot find at home
since you are aware of this stat, what is your source for it?
It was also a common pattern for immigration into North America from Europe in the 19th and early 20th centuries.
So, another explanation for those less paranoid is that the "young men" are trailblazers.
For the more paranoid, they're invaders. Which is basically what the paranoid say and said about the Salvadorans, the Mexicans, the Italians, the Poles, the Irish, etc.