Tom Watson, Mr Corbyn’s deputy, and shadow foreign secretary Diane Abbott came to the defence of the opposition leader, and said the row was overshadowing the rest of politics at a time of huge importance less than 100 days before Brexit.
Mr Corbyn was forced to deny calling Mrs May a “stupid woman” after the final Prime Minister’s Questions of the year descended into a bitter row.
He was brought back to the Commons to tell MPs he used the phrase “stupid people” after TV cameras picked him up as he said something inaudible to those sat with him after the Prime Minister likened his attempt to force a confidence vote in her to a Christmas pantomime.
Commons Leader Andrea Leadsom on Thursday said Mrs May’s performance was just “parliamentary banter”.
Ms Abbott said Tory MPs had “put on a display yesterday which Hackney primary school children would have been ashamed of”.
She told BBC Radio 4’s Today programme that Mr Corbyn was an honest man and “if he has something to say sorry for he will always say sorry”.
She added: “To me it was contrived, staged behaviour, and the British people might wonder why the Tories will stage a mini-riot in Parliament over that but are not staging a mini-riot over the tens of thousands of people who are newly on Universal Credit and are facing Christmas with no money.”
Mr Watson told Good Morning Britain that Mr Corbyn had “got up at the dispatch box, he denied using those words, and that is good enough for me”.
Mr Watson added: “On a very personal level, I have been around a long time so you try not to let these things get to you.
“But of course, we have got Brexit, we have got loneliness, we have got millions of pensioners facing their TV (licence) cut, and being on TV talking about what Jeremy did or did not say is not great. But that is British politics for you.”
On Wednesday night the Conservatives continued their attack on the Labour leader and attempted to drum up support for Mrs May’s party as the dispute rumbled on.
In a message to supporters, the party’s vice chair for women Helen Whately pleaded with them to join the Conservatives at £25 a year to “show Corbyn he can’t get away with calling Theresa May a ‘stupid woman’”.
She said: “This is just the latest in a long line of misogynistic behaviour from Corbyn and his top team.”
The video footage went viral on social media and sparked a furious debate in the Commons, with Tory MPs demanding Mr Corbyn be brought back to apologise.
Mr Corbyn flatly denied using the sexist phrase, telling MPs: “I referred to those who I believe were seeking to turn a debate about the national crisis facing our country into a pantomime as ‘stupid people’.
“I did not use the words ‘stupid woman’ about the Prime Minister or anyone else, and am completely opposed to the use of sexist or misogynist language in absolutely any form at all.”
The almost immediate circulation of footage of Mr Corbyn prompted uproar in the Commons, with shouting and heckling as a succession of MPs demanded action from Speaker John Bercow.
He triggered a furious response from a slew of female MPs, including Mrs Leadsom, after refusing to take immediate action because he had not seen the incident.
The Speaker later returned and told MPs that while it was “easy to see” why Mr Corbyn’s words might have been construed as “stupid woman”, “nobody can be 100% certain, that includes professional lipreaders”.
He added: “I will naturally take, and would be expected to take, the word of any right honourable or honourable member. It’s reasonable to expect the House to do the same.”
Mrs Leadsom said she believed Mr Corbyn called the Prime Minister a “stupid woman”, telling the Today programme: “That is how it looks to me.”
She defended the Prime Minister’s use of pantomime language during her PMQs attack on Mr Corbyn, saying: “Anyone in the country would see the difference between a bit of parliamentary banter and somebody calling someone a ‘stupid woman’.”