These are just the people that are most likely to be able to get out of the country. That doesn't mean they don't have a good reason for doing so but still. Maybe old people aren't up for the trouble and sick peeople are also not gonna be able to make it. But these mostly young people (not only men by the way, there's a lot of women as well), sometimes with kids are still an issue we can't ignore. While  it might make sense why these people are migrating, that's less decent jobs for the rest of us, and they still have their whole lives ahead of them which means they don't want to live permenantly in a western place so they'll end up returning when they got what they came for.