Peggy Drexler is the author of "Our Fathers, Ourselves: Daughters, Fathers, and the Changing American Family" and "Raising Boys Without Men." The opinions expressed in this commentary are hers.

(CNN) Six weeks after the first stories broke alleging that Hollywood producer Harvey Weinstein engaged in a decadeslong pattern of sexual harassment (he denies it), the list of men accused of similar acts keeps getting longer. Some offer denials, but others offer more nuanced "explanations":

Meanwhile, the Alabama Republican party has reiterated its support of Senate candidate Roy Moore ( as has President Trump ), who faces allegations of sexual abuse (he denies them), and the number of women accusing former President George H.W. Bush of groping has reached a whopping eight. Responding to four of the allegations last month, Bush's spokesman "explained" that elder Bush "has patted women's rears in what he intended to be a good-natured manner," and apologized. For the more recent allegations, he offered no comment.

These and the many other men against whom allegations have been made -- some quite a bit more serious than patting "women's rears" -- are all ambitious, smart, powerful men -- surely men whom one would think might know better than to behave in this way. In some instances, famous men are alleged to have forced their tongues into an unwilling woman's mouth, walked around naked , or pulled out their penises to show around

So why do they do it? And why are there so many? As was proved by the viral #metoo campaign , which saw hundreds of thousands of women sharing their own stories of sexual assault, the problem is rampant; sadly, less an exception than the rule.

One possible explanation points to a deeply ingrained, hard to shake and society-wide sexism that teaches men that women are less dominant. Many men -- and women, for that matter --still believe men do the asking out and the chasing (often, too, the paying for dinner).

Setting aside the flat-out predators who walk among us, this misunderstanding of men's roles may lead some men, especially those in the throes of sexual attraction, to let their desires override their intellect and their knowledge of what is wrong and what is right.

It would be nice to imagine that, in 2017, sexism is an outdated notion in the mainstream: After all, this is the same culture that created not just "The Bachelor" but also "The Bachelorette." Times have changed, right? As Harvey Weinstein put it in his official statement, "I came of age in the '60s and '70s, when all the rules about behavior and workplaces were different. That was the culture then."

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And yet there's SO MUCH evidence it's the culture now, too. We've only got to look at the defeat of a highly qualified, highly prepared, definitely female presidential candidate by a less qualified male opponent (himself, let's not forget, accused of sexual assault by multiple women; he denies it) as proof that sexism lives on. That he largely based his campaign on bluster and bullying -- and was elected by 52% of men and 41% of women -- only strengthens the point.

Another explanation for the problem of sexual harassment, and one that similarly has roots in sexism, is that we still have a hard time defining (or agreeing on) what constitutes sexual harassment and assault.

A small recent survey by car-selling app Instamotor found that many men aren't clear on what sexual harassment is. Two in every three men surveyed didn't think repeated unwanted invitations to drinks, dinner, or dates was sexual harassment. One in five didn't think sexual harassment should be a fireable offense.

What's more, many such behaviors are learned: In one story that ran on NPR, a "reformed catcaller" described growing up watching older men he admired holler at women in his Brooklyn neighborhood. "All my life I heard girls are cats and boys are dogs ...," he said. "Hollering at women on the street was what guys were supposed to do, or so I thought."

Certainly, many of the accusations we've all been hearing over the past weeks seem to extend well beyond gray areas. But if there is confusion about those gray areas -- that is, what defines harassment at all -- it's possible there could be confusion about what is absolutely off-limits, and what is, perhaps, part of some men's archaic or delusional idea of the male-female mating dance.

No woman asks to be assaulted or harassed -- or touched in a manner that makes her feel uncomfortable. And yet, how else to explain the Bush family spokesman admitting the former president of the United States would often "pat women's rears" in a "good-natured manner" as "David Cop-a-feel"?

Which means we need to do a better job making damn sure every single man -- and woman -- is clear about what constitutes inappropriate behavior.

That's hopefully what the current conversation will do. In addition to holding men accountable for their past actions, it will open up dialogue so that misunderstanding is no longer an acceptable excuse. Because let it be known: Whether you're a man or a woman, good-natured rear-patting of someone you aren't 100% sure would welcome it is never as good-natured as you might like to believe.