Ms Webbe insisted that she had not meant to allow speakers at the 2017 Labour party conference to use antisemitic tropes during a debate about adopting new rules to clampdown on Jew hate.
During the angry debate, delegates repeatedly attacked the party's NEC for working with the Jewish Labour Movement to implement the changes.
Naomi Wimborne-Idrissi, from the pro-Jeremy Corbyn Jewish Voice for Labour group, claimed Jews promoting the rule change had been "running" to brief right-wing newspapers including the Mail and the Telegraph.
Ms Webbe said she tried to "give people on all sides a chance to speak" as chair. "I was not aware of antisemitism and, if I was, I would have said something," she said.
“To get the rule change through conference was a big deal and I think that is something to be celebrated. It is not true to say I allowed antisemitism.”
She continued: “It pains me to hear from the victims. I find antisemitism abhorrent and I want the party to be a place that doesn’t just say it welcomes everyone, it makes them feel it."
She said she would not ignore “the concerns of the Jewish community. I condemn the attacks and the emotional abuse that people have experienced".
She added: “I know people have spoken up about what they have experienced and that they can be demonised... I don’t think that should happen to anyone.
"I have experienced racism myself so I know what it feels like. It is my mission to make the Jewish community feel welcome.”
Ms Webbe's appointment also caused alarm because of her past defence of Ken Livingstone.
She said she did not condone Mr Livingstone’s comments in 2005, when he likened journalist Oliver Finegold to a Nazi guard, nor did she support his recent comments about Hitler and Zionism that led to him to quit the party after being suspended.
But she stood by her decision to write a letter to the Guardian in defence of the former London Mayor in 2006 after he was suspended as mayor for four weeks over his encounter with Mr Finegold.
Ms Webbe worked as an adviser to Mr Livingstone in 2000 and 2004 and, in the Guardian letter, said his suspension “smacked in the face of true democracy”.
“His history of work in the anti-racist movement is unquestionable,” she wrote in the letter.
She told the JC: “I was asked to record his anti-racist credentials accurately as the chief executive of the Race Equality Council.
“At the time, I think that context was important. He had been elected by London, would we call those that voted for him racist?”
Ms Webbe, who was tipped to land the new role with the backing of Mr Corbyn’s office, said she had experience of working with the Jewish community and vowed to support them.
She said she worked with the Board of Deputies as chief executive of Westminster Race Equality Council, adding: "Fighting antisemitism is something that I take seriously."
“I am the best person for the job,” she added. “My experience in terms of tackling racism is second to none. I have spent my entire life dealing with these issues."
Ms Webbe, an Islington councillor, said it was unacceptable that disciplinary cases were taking months and sometimes years to deal with.
“I think we have had processes that worked for the smaller membership and not for the thousands we have now.
“We used to deal with half a dozen complaints now we have hundreds.”
She promised to make sure the disputes process was "fit for purpose and served all our members”.
She was elected after the previous chair, Christine Shawcroft, stood down from the NEC after a leaked email revealed she backed a party member who was suspended over alleged Holocaust denial.
