Rachel Riley has accused Manchester United of "gaslighting" and "green lighting" abuse for their handling of the decision to part company with Mason Greenwood.
Greenwood's exit was confirmed on Monday after a six-month internal investigation into his conduct.
It came after charges against the player, including attempted rape and assault, were dropped in February.
"Right decision, horrendous statement," television presenter Riley wrote.
In explaining the lengthy process behind their decision, a Manchester United statement claimed Greenwood "did not commit the offences in respect of which he was originally charged", adding: "Based on the evidence available to us, we have concluded that the material posted online did not provide a full picture."
An open letter from chief executive Richard Arnold also said: "While we were unable to access certain evidence for reasons we respect, the evidence we did collate led us to conclude that Mason did not commit the acts he was charged with".
And Greenwood issued a statement saying he accepted he had "made mistakes" and took his "share of responsibility", but added: "I did not do the things I was accused of."
Arnold said that Greenwood's potential reintegration was "one of the outcomes we considered and planned for" but that "several outcomes have been contemplated and planned for" and his view "evolved".
However, United fan Riley claimed the club's statements were "gaslighting" - a term used to describe a form of manipulation where a person is given false information that leads them to question the truth.
She also accused the club of "green lighting" abuse on social media, saying: "This overreaching statement will put wind in the sails of abusers and send a message to victims it's more trouble than it's worth to report alleged abuse. It's so disappointing to see my club contribute to the culture that upholds this."
"The question before them [United] was not whether Mason Greenwood may be found guilty in a criminal, or even civil court, it was whether he's fit to wear the United badge, to be a role model to kids who look up to footballers as heroes, and have his name proudly displayed on shirts sold in the club shop," Riley wrote on X, formerly known as Twitter.
Riley had previously said she would stop supporting United if forward Greenwood stayed at the club.
She also told podcast The News Agents: "I think it's gaslighting for people to have two statements saying, Mason Greenwood himself saying he's been cleared of all charges - which is not the case, the claims were dropped because the key witness dropped out - and they [United] claim new evidence.
"I've never been more ashamed of the club. I think it's just a disgrace. And they had another opportunity to make it right, make a good statement and they have just greenlighted the abuse that's been going on on social media."
Writing on X on Tuesday, the Countdown co-presenter said: "I've been a red since before I was born, I've passed it on to my baby girls and some of the all-time best times of my life have been working with and cheering on Man United, so I write with such a heavy heart - as a club we've handled this appallingly."
BBC Sport has approached Manchester United for comment.
'Arnold should consider position'
England international Greenwood was arrested in January 2022 following allegations surrounding material published online.
He was later charged in October 2022 with attempted rape, controlling and coercive behaviour and assault occasioning actual bodily harm.
After the charges were dropped in February 2023, the Crown Prosecution Service said key witnesses had withdrawn and new material had come to light, meaning there was "no longer a realistic prospect of conviction".
United then started their own investigation.
On Monday the club issued three statements: from the club, Greenwood and an open letter from Arnold to fans. They came after a number of delays amid fierce debate about Greenwood's potential reintegration at Old Trafford.
The club said they wanted to consult with their women's team, some of whom were part of England's World Cup squad playing in Australia, before announcing a decision about Greenwood's future.
Arnold said the club had "limited powers of investigation" and "were reliant on third-party cooperation" as they "sought to collate as much evidence as possible to establish facts and context".
He said the extra evidence included the alleged victim requesting the police to drop their investigation in April 2022, and the club receiving alternative explanations for the material that was posted online.
Former United player Gary Neville said United's handling of the Greenwood investigation had been "pretty horrible", lacked strong leadership and should have been dealt with independently.
Riley told The News Agents podcastexternal-link that Arnold should consider his position.
"I've seen first hand how little is known, even amongst professionals who are supposed to be dealing with this - I include the police, I include social services," she said.
"If they don't know the intricacies, I don't know how a CEO at Manchester United who has multimillion pounds at stake is in any position to make a judgement on what has happened, especially having not consulted abuse charities."
In her social media post, Riley said the situation needed "trained, qualified, experienced experts" and it "goes far beyond the scope of what United were tasked with".
"It is absolutely right a thorough investigation should take place. Yet experts could have used their knowledge to help United navigate the process so we could trust the outcome. And an external party with no vested interests would have been far more credible," she added.