Though the party was happy to release more details of the email in its defence, it told the JC it could not identify the Jewish member whose case Mr Milne was discussing for data protection reasons.
The activist Mr Milne was discussing was Glyn Secker, a member of the pro-Corbyn fringe group Jewish Voice For Labour (JVL), whom JLM accused of "long and well documented history of incendiary hate speech".
A JLM spokesperson agreed Mr Milne’s full quote was "worse" in the wider context the party provided.
“Secker has a long and well documented history of incendiary hate speech. Milne’s direct intervention was clearly an attempt to direct party staff to cancel the suspension of a political ally of the leadership,” they said.
Mr Secker had been suspended in March 2018 after he was found to be a member of Facebook group Palestine Live, where antisemitism and Holocaust denial were shared.
Mr Secker’s suspension was eventually lifted after he was not found to have said anything in the group.
Mr Secker had been chosen to be suspended by Labour’s former head of complaints Sam Matthews, whom the leadership team hastily asked to come up with three members of the group to suspend so the party could announce it was taking action.
“They wanted me to take just 20 minutes on a process that needed to be done thoroughly and methodically,” Mr Matthews, one of the whistleblowers who spoke to Panorama, told the JC.
Mr Secker was later accused of blatant antisemitism when he accused Jewish community leaders of being “part of the problem”.
Addressing a pro-Palestinian march in London in May, he said they were "turning a blind eye to the extreme right" and asked: "What are Jews doing in the gutter?"
He later tried to apologise, saying: "I allowed my outrage to dictate my expression and I am not pleased with the language I used."
JVL has consistently downplayed allegations of antisemitism. Jon Lansman, the founder of pro-Corbyn campaign group Momentum, called it "part of the problem and not part of the solution to antisemitism in the Labour Party."
Mr Lansman also said of the group: "Too many of its members self-define as 'Jews' only to attack other Jews."
When asked to comment on Mr Secker, JVL co-founder Naomi Wimborne-Idrissi said: "JLM's comment about a Jewish party member with an unblemished record in fighting racism of all kinds is beneath contempt and, as usual in such cases, evidence-free."
After Panorama was broadcast, the Board of Deputies said Mr Corbyn, Mr Milne and Labour General Secretary Jennie Formby “are personally responsible for having turned a once-great, anti-racist party into a cesspit of antisemitism”.
Board president Marie van der Zyl said the programme “gives added weight to what we have suspected all along.
"It suggests that the issue of antisemitism has been treated with disdain by the Labour leader and as a joke by Seumas Milne, and that Jennie Formby and her appointments have repeatedly obstructed justice in disciplinary cases.”
She said the behaviour exposed by former staff was “a terrible indictment of a party unable and unwilling to confront racism in its own ranks”.
She added: “Weak excuses are belied by the observable results, where clear offenders are let off with little to no punishment.”
Chief Rabbi Ephraim Mirvis said Labour’s antisemitism problem was an “agonising saga” and accused Mr Corbyn’s party of being “complicit” in Jew-hate.
He said “little has been achieved” to tackle the problem.
Holocaust Educational Trust Chief Executive Karen Pollock said the “shocking evidence shown in the devastating and heartbreaking Panorama documentary makes it clearer than ever that the Labour Party has deeply embedded institutional antisemitism in its processes, culture and leadership."
Labour has been contacted for comment.
