The author was accused of transphobia earlier this year after comments she made on social media about gender identity, and the row has been reignited after it was revealed her latest detective novel Troubled Blood features a cross-dressing serial killer.
Harry Potter actor Coltrane, 70, told the Radio Times: “I don’t think what she said was offensive really. I don’t know why but there’s a whole Twitter generation of people who hang around waiting to be offended.
Watch: Cynthia Nixon shares transgender son’s reaction to J.K Rowling’s remarks
“They wouldn’t have won the war, would they? That’s me talking like a grumpy old man, but you just think, ‘Oh, get over yourself. Wise up, stand up straight and carry on.’”
He added: “I don’t want to get involved in all of that because of all the hate mail and all that s***, which I don’t need at my time of life”.
It emerged at the weekend that Rowling’s latest instalment in her Cormoran Strike detective series, published under the pseudonym Robert Galbraith, centres around a cis male serial killer who dresses as a woman to kill his cis female victims.
The first review for Troubled Blood, which appeared in The Telegraph at the weekend, describes it as a, “book whose moral seems to be: never trust a man in a dress.”
The second novel in the series, The Silkworm, was previously criticised over its depiction of a trans character described as, “unstable and aggressive”.
Rowling's detective stories have been adapted into BBC TV series Strike starring Tom Burke and Holliday Grainger.
Rowling, 55, was accused of transphobia after a series of posts on Twitter in June, responding to a story with a headline which read: “Opinion: Creating a more equal post-COVID-19 world for people who menstruate.”
She tweeted: “‘People who menstruate’. I’m sure there used to be a word for those people. Someone help me out. Wumben? Wimpund? Woomud?”
She went on to defend her comments saying: “If sex isn’t real, there’s no same-sex attraction. If sex isn’t real, the lived reality of women globally is erased. I know and love trans people, but erasing the concept of sex removes the ability of many to meaningfully discuss their lives. It isn’t hate to speak the truth.”
Rowling was criticised for her remarks by Harry Potter stars including Daniel Radcliffe, Emma Watson and Fantastic Beasts star Eddie Redmayne.
Radcliffe apologised to Harry Potter fans for Rowling’s comments, and actress Katie Leung, who played Cho Chang in the movies, also commented.
Watson, who starred as Hermione Granger in the franchise, said: "Trans people are who they say they are and deserve to live their lives without being constantly questioned or told they aren't who they say they are.
"I want my trans followers to know that I and so many other people around the world see you, respect you and love you for who you are."
Redmayne, who stars in Harry Potter spin-off Fantastic Beasts and Where to Find Them, said in a statement: “As someone who has worked with both J.K. Rowling and members of the trans community, I wanted to make it absolutely clear where I stand."
“I disagree with Jo’s comments. Trans women are women, trans men are men and non-binary identities are valid.
“I would never want to speak on behalf of the community but I do know that my dear transgender friends and colleagues are tired of this constant questioning of their identities, which all too often results in violence and abuse. They simply want to live their lives peacefully, and it’s time to let them do so.”