Channel 4 News journalist Fatima Manji has said the press regulator's decision not to uphold her complaint about Kelvin MacKenzie is "frightening".
Writing in the Sun in July, MacKenzie said a reporter wearing a headscarf should not have been allowed to report on the Nice terror attacks.
Manji said Ipso's clearing of MacKenzie signified "open season" on minorities.
But MacKenzie told BBC News there was a "legitimate debate" to be had about journalists wearing symbols of faith.
In a statement to the corporation, he said: "I agree 100% that no Muslim should be prevented from covering any story.
"But there is a legitimate debate about whether it is appropriate for journalists to wear prominent symbols of their faith on air, particularly when reporting on stories with a religious angle."
He also drew attention to the BBC's own debate around the issue several years ago, when bosses at the corporation were considering what was appropriate for newsreaders to wear.
MacKenzie added: "Let's not lose sight of that fact that for many people, including Muslims, the hijab is a symbol of the subjugation and oppression of women. In some countries, women are physically attacked, arrested and imprisoned for not covering their heads.
"Whatever your perspective, it is an important debate and we should not be banned from discussing it."
Speaking to BBC Radio 4's Today programme on Thursday morning, Manji said: "I think the fact that Kelvin MacKenzie can write a column and suggest that I am somehow sympathetic to a perpetrator of a terrorist attack, that somehow I am not like the rest of us, that I am the other, means that other people are now open to attack."
'Embarrassed and ashamed'
"It was upsetting enough to find my picture in what is Britain's most widely read newspaper next to the words 'Muslim terror attack,'" she told Mishal Husain.
"It was upsetting enough to find myself the latest victim to Kelvin Mackenzie's tirade. But now to know that has been given the green light by the press regulator and that effectively it is open season on minorities, and Muslims in particular, is frightening."
Manji added that she had been "contacted privately by individuals who work at The Sun and at News UK to say they were embarrassed and ashamed that MacKenzie was allow to peddle such hatred".
In his original column, MacKenzie asked: "Was it appropriate for [Manji] to be on camera when there had been yet another shocking slaughter by a Muslim?"
He argued the hijab was a "religious statement" and questioned whether a Christian would be able to wear a cross prominently on television.
Manji told the BBC: "This debate about religious symbols to me is a manufactured debate by the Sun and Kelvin MacKenzie. He is not a public philosopher of our time, he's not interested in religious symbols
"A third of the victims [in Nice] were Muslim, a 62-year-old grandmother was slaughtered that night, she, like me, was called Fatima and also wore a headscarf."
In its ruling, published on Wednesday, the Independent Press Standards Organisation (Ipso) said he was "entitled to express" his view.
"The article did not include a prejudicial or pejorative reference to the complainant on the grounds of religion."
"While the columnist's opinion was undoubtedly offensive to the complainant, and to others, these were views he had been entitled to express."
Responding to the ruling, Ben De Pear, the editor of Channel 4 News, said: "Whilst we agree that freedom of expression is a fundamental right, we do not believe that it should be used as a licence to incite or discriminate."
"We see no reason why a Muslim journalist should be prevented from covering any story and Fatima will continue to report and present the news on the issues of the day with impartiality and depth."