She also said there may have been an “anti-feminist” element to the storm of criticism.
Speaking to the Sunday Independent, she said: “I think Sabina Higgins’ own statement has resolved the issue and given clarity as to the nature of it appearing on the website.
"But obviously she is entitled to express her view as an independent person. I saw the backlash against her and I thought it was disproportionate.”
Asked if there may have been an element of sexism to the backlash that Ms Higgins received, Ms Bacik said: “I don’t know if it might have been different if she had been a male. It is hard to know.
"We have had no similar situation where a male partner of a president has written publicly to a paper, so it’s difficult to know if there was misogyny there.
"People are entitled to express their opinions as private citizens and as an independent person she is entitled to her view.
“I know Sabina for a long time and I know her great track record on feminist issues and as an activist and a campaigner, and she doesn’t leave that behind [when her husband enters public office]. Nobody would expect her to.
"There may have been some anti-feminist element to it. But then people very genuinely disagreed with what she was saying.”
Ms Bacik called for greater “clarity” in the future on what is allowed on Ms Higgins’ “dedicated section” of the President’s official website to enable Ms Higgins to take on a more “public role” going forward.
The letter, in which Ms Higgins called for a negotiated settlement of the war in Ukraine, was published on Mrs Higgins’s own dedicated section of the president.ie website.
To view the article, a user had to click on the ‘Sabina Higgins’ link from the main page.
Ms Bacik said: “Maybe we do need more clarity on Sabina’s section of the website. It’s good to know about the part of the website that Sabina uses. I think that resolved matters for most people.
"Often a spouse or partner does take a very public role themselves and that may well be a way forward with a much more formalised nature of the role.”
Ms Higgins made the comments weeks after Ukrainian President Volodymyr Zelensky said the war in Ukraine could only be resolved through “diplomacy”.
Speaking on national TV in May, he said the war could only come to a conclusive halt "at the negotiating table".
Meanwhile, Ms Bacik has welcomed the resignation of retired judges Frank Clarke and Peter Kelly from the Dubai International Financial Centre courts after she said it was not appropriate for them to hold the posts.
“I commend them,” she said. “I think it was an appropriate and sensible thing to do — and to be fair they acted very quickly, and the positive is that it has highlighted the deeply oppressive and misogynistic nature of the Maktoum regime in Dubai.
“Most lawyers I knew and spoke to were glad someone has spoken out, and agreed with my position on it.”
She also addressed recent polls which suggest that only 4pc of people would vote for the Labour Party in an election.
“Really the issue for Labour is to rebuild and grow support for our values,” Ms Bacik said.
"We also saw in the by-elections in Dublin Bay south last summer we confounded all the pollsters’ expectations. What it shows is there is a strong appetite for change — particularly among younger voters.”