It's an aversion to seeming contrived. Men just fit the trope and archetype better and directors will naturally play it safe. It isn't just the opposite of what a woman "should be", it's the opposite of how a woman generally wounds you and to be frank I'd rather a werewolf tear me limb from limb compared to the malice even the average woman is capable of.
And believe you me a female werewolf can be done, but you also have to remember that the era of the monster movie is kind of over.
It's an aversion to seeming contrived. Men just fit the trope and archetype better and directors will naturally play it safe. It isn't just the opposite of what a woman "should be", it's the opposite of how a woman generally wounds you and to be frank I'd rather a werewolf tear me limb from limb compared to the malice even the average woman is capable of.
And believe you me a female werewolf can be done, but you also have to remember that the era of the monster movie is kind of over.