Because of men's empathy they gave women power, hence today women saying all men are trash is said to be justified because women were/are oppressed. Most men do not care if a woman says this. The opposite is true, where any woman would probably get butthurt if you said all women are trash.
Of course, when they say men are trash, they are usually just angry that Chad treated them like a fucktoy or something. But the empathetic gender (men) always let women say this because of a perceived legacy of oppression and collective guilt on their part (even though the average man throughout history lived just as horrible if not more horrible life than the average female).