The problem is that “women are attracted to nice guys” implies that “being nice” itself is “enough” to be attractive. Guys get this idea that all they have to bring to the table is “I’m not a jerk” and the ladies will fall into their laps. The problem is, the jerk down the road is in better shape, has interesting hobbies, and/or has a real, dependable job. Being “nice” is like having two slices of bread and saying you have a sandwich. If you don’t put anything between the bread slices, everyone’s going to opt to order the burrito instead because it’s got an actual filling.