For the most part, women aren't saying that all men are dangerous.
We're saying that a significant percentage of them are—as established by the fact that the majority of women have experienced sexual harassment and/or assault at least once—and that "bad" men and "good" men are often indistinguishable from each other... for the first few minutes, hours, days, months, or even years of knowing them.
And then there are the many men who may not actively harass or assault women, but look away and remain silent when they witness their friends doing it. Those men are unsafe, too.
Anyone who perceives this hypothetical situation as "sexist" is not bothering to actually listen to what women are saying, which tracks. Hit dogs holler.