As you say virtually every sentence of that is factually inaccurate, not merely opinion that I disagree with.
The main “charge” against Stonewall is conveniently vague,
Opinion, but people are definitely writing about specific things stonewall have done.
but can be traced to a report commissioned by the University of Essex that looked at the cancellation of a seminarr* at which an academic who is seen as “gender critical” was due to speak, as well as another cancelled event.
Lying by omission, two female professors has their events cancelled because of their views.
The way it's written gives the impression that it could have been a coincidence. And not mentioning who was cancelled hides the fact that women were targeted.
Although not directly related to the event in question, the report touched on Stonewall’s Diversity Champions programme, which exists to advise employers on how to operate inclusive of LGBTQ+ people. It claimed that Stonewall Diversity Champions policies do not “accurately state the law”.
It "claimed" stonewall policies don't accurately state the law because stonewall policies don't accurately state the law! It gave evidence of this the fact that women had been denied their freedom of speech because of the inaccurate representation of the law from stonewall and the culture created by this.
The Guardian obviously don't have any fact-checkers because this piece is a disgrace.