Canadian author Margaret Atwood is facing a social media backlash after voicing concerns about the #MeToo movement and calling for due process in the case of a former university professor accused of sexual misconduct.

Writing in the Globe and Mail, Atwood said the #MeToo movement, which emerged in the wake of sexual assault allegations against Hollywood producer Harvey Weinstein, was the symptom of a broken legal system and had been “seen as a massive wake up call”.

However, she wondered where North American society would go from here. “If the legal system is bypassed because it is seen as ineffectual, what will take its place? Who will be the new power brokers?” Atwood asked.

She raised the possibility that the answer could leave women divided. “In times of extremes, extremists win. Their ideology becomes a religion, anyone who doesn’t puppet their views is seen as an apostate, a heretic or a traitor, and moderates in the middle are annihilated.”

The 78-year-old author of The Handmaid’s Tale drew a parallel between these concerns and those who accused her of being a “bad feminist” after she signed an open letter last year calling for due process for a University of British Columbia professor facing allegations of sexual misconduct.

The university’s administration released few details on the case against Steven Galloway, the former chair of the creative writing program, saying only that he was facing “serious allegations”. After a months-long investigation he was fired, but the official findings were never released. The faculty association said in a statement that all but one of the allegations, including the most serious allegation, were not substantiated.

In her piece, Atwood pointed to the university’s lack of transparency around the allegations and noted that Galloway had been asked to sign a confidentiality agreement.

“The public – including me – was left with the impression that this man was a violent serial rapist, and everyone was free to attack him publicly, since under the agreement he had signed, he couldn’t say anything to defend himself,” she wrote. “A fair-minded person would now withhold judgment as to guilt until the report and the evidence are available for us to see.”

She likened the affair to the Salem witch trials, in that guilt was assumed of those who were accused. This idea of guilt by accusation had at times been used to usher in a better world or justify new forms of oppression, she wrote. “But understandable and temporary vigilante justice can morph into a culturally solidified lynch-mob habit, in which the available mode of justice is thrown out the window, and extralegal power structures are put into place and maintained.”

Many online took issue with her view. “If @MargaretAtwood would like to stop warring amongst women, she should stop declaring war against younger, less powerful women and start listening,” wrote one person on Twitter. “In today’s dystopian news: One of the most important feminist voices of our time shits on less powerful women to uphold the power of her powerful male friend,” wrote another.

Some accused Atwood of using her position of power to silence those who had come forward with allegations against Galloway. “‘Unsubstantiated’ does not mean innocent. It means there was not enough evidence to convict,” read one tweet.

Others defended Atwood. “Genuinely upsetting to see Margaret Atwood attacked for pointing out that ‘innocent until proven guilty’ is the key to a civilised society. That has to still be a thing, yes? How can that suddenly be a bad thing?”

In a statement to the Guardian, Atwood pointed to the Universal Declaration of Human Rights, echoing an earlier tweet in which she defended her view by noting that endorsing basic human rights for everyone was not equivalent to warring against women.

Her opinion piece, she said, was meant to highlight the choice we now face; fix the system, bypass it or “burn the system down and replace it with, presumably, another system”.