I think in some cases in Berlin, some men did organize to 'keep an eye' on migrants attacking women and kids, but in many cases, groups of local men would be overwhelmed by the sheer number of migrants they let in.
Look at the video of the assault on the police officer I spoke of the other night and all the people who were around and nobody helped her out.....
https://www.youtube.com/watch?v=KRjGcAay46s