It's because women are evolutionarily hardwired to seek men who are a little bit dangerous and wild. Such men are the ones who will be capable hunters and protectors They then "civilize" them into domestic family life and broader mainstream civilization. We have examples of this dating back to ancient literature with The Epic of Gilgamesh.

Historically, this worked pretty well. Murderers were rare, and were generally quickly dispatched by their societies. Close communities and draconian laws kept order. Most violence that did exist was intertribal and socially condoned.

Three big issues muck this all up.

1.) The erosion of shared moral and cultural values has lead not only to more crime, but it also makes people's expectations of each other less accurate.

2.) Increased urbanization leads to anonymity, less accountability, and less empathy towards one's neighbors.

3.) The emasculation and infantilization of noncriminal Western men. When women cannot find traditional masculinity, they will seek its perverted form in black gang culture or Islam.