The most popular set of photos used to spread this meme are scenes of a group of migrants arriving by train in Munich (not at a border crossing) that are exclusively young men; for reasons not entirely clear to me they were on a separate train from the women and children in the same group, who arrived the next day.

There's also pictures of groups of boat refugees that show a large imbalance, which is true of those using that mode of transport, who often leave women and children to follow on once they've found a place because of the extreme danger of the route (which, yes, might evidence some degree of non-progressive concept of gender roles, but that's not the issue being raised.)