It would take a mere 10 seconds of googling to find the answer to that question as he is literally asked about it every few hours on twitter or in interviews. And every single time he explains it but it seems to fall on deaf ears.
> I understand those who are heavily offended by that viewpoint
I personally don´t understand those people because they are not really listening to the argument. They are selectively hearing what they want to hear. In your "question" there is an embedded assumption that order (masculine) is "good" and chaos (feminine) is "bad". And that´s why people get offended; if they didn´t equate chaos with bad, there would be no reason to get offended. This happens because they are not _actually_ reading Peterson. They are reading what they _think_ someone like Peterson would say but in doing so they miss the point completely.
Peterson argues that chaos in literature is most often presented as feminine (mother nature for instance) and order is presented as masculine most often (God, the heavenly father for instance). At any point in time, order OR chaos can both take hold to varying extreme degrees, which is not good for society. Example: Totalitarian states (extreme order/masculine) are bad, but so is anarchy/chaos and the complete lack of order. Both extreme order and extreme chaos are bad he argues constantly.
Would it be any better if Peterson argued that chaos was masculine and order was feminine? not really, people would still get offended because that´s what people want to be. They don´t actually stop and listen to what is being said, which is unfortunate :/