Controversial academic Jordan Peterson has publicised the reinstatement of his self-help book 12 Rules for Life at New Zealand book chain Whitcoulls, after it was removed from sale following the Christchurch attacks.

Last week, images of an email from Whitcoulls were posted on social media in which a spokeswoman for the bookseller told a customer that it had taken the decision to remove Peterson’s book from sale “in light of some extremely disturbing material being circulated prior, during and after the Christchurch attacks”.

“As a business which takes our responsibilities to our communities very seriously, we believe it would be wrong to support the author at this time,” wrote Whitcoulls in the email, which was quoted by the New Zealand Herald. During a tour of New Zealand in February, Peterson was photographed with a fan in a T-shirt bearing the slogan: “I’m a proud Islamaphobe”.

Peterson’s supporters opposed Whitcoulls’ decision online, pledging not to spend money in the shop and pointing out that the chain continued to stock books including Mein Kampf. On Tuesday, Whitcoulls also removed Full Auto Volume 1, a book explaining how to turn semi-automatic assault rifles into fully automatic weapons, after the New Zealand Herald queried why the bookseller was selling it.

On Wednesday morning, Peterson tweeted that the chain had reinstated the book, with the Whitcoulls website showing that the title is in stock in its branches, but not online. The chain did not respond to requests for comment.

Peterson, a psychology professor from Toronto, styles himself as a “professor against political correctness”. His bestselling 12 Rules for Life, published in 2018, provides a “startling message about the value of personal responsibility and the dangers of ideology”, according to its publisher. Hari Kunzru called it “oppressive” and “hectoring” in the Guardian.

The author visited Christchurch during his tour, where he spoke about toxic masculinity, weeks before the terror attack in two mosques in the city which killed 50 people. Writing on his blog at the beginning of March he dismissed what he called “radical leftist critics” for saying that he was appealing “to disaffected and angry young white men”.

“There has not been a single event of any violent or even vaguely aggressive nature at any of the venues I have spoken at,” wrote Peterson, adding that: “All the people who attend are by no means young or white, much to the dismay of my critics.”

The move by Whitcoulls follows Cambridge University’s decision last week to rescind the offer of a visiting fellowship to Peterson, saying that the university is “an inclusive environment and we expect all our staff and visitors to uphold our principles. There is no place here for anyone who cannot.”

In a lengthy response on his blog, Peterson called the decision “deeply unfortunate” and accused the university of “kowtowing to an ill-informed, ignorant and ideologically-addled mob”.

Cambridge vice-chancellor professor Stephen J Toope revealed in a statement on Monday that the decision was linked to Peterson being photographed with the fan wearing the Islamophobic T-shirt. “The casual endorsement by association of this message was thought to be antithetical to the work of a Faculty that prides itself in the advancement of inter-faith understanding,” he said.

Peterson told the Times on Tuesday that he had a “strong belief that people should be allowed to express themselves as they see fit and I haven’t invoked a dress code at my lectures”. But he added that he has now asked the company which handles the photos at his events to ensure that those pictured with him “refrain from more provocative political garb, given that the fallout can be used by those who are not fond of me (a serious understatement) to capitalise on the opportunity the photos provide”.

Peterson also challenged his critics to find evidence that he has spoken “a single phrase that marks me as a prejudiced person regarding sex, race, ethnicity or, indeed, any of the multiplicity of identities that have become so quickly and strangely dominant in our culture so recently”.

Last year, he told the New York Times that “the people who hold that our culture is an oppressive patriarchy, they don’t want to admit that the current hierarchy might be predicated on competence”.