I take your overall point that saying 'All men are rapists' in the workplace would be offensive.
You are holding on to the fact that the hearing believed that she said those words, although she denies that she did.
OK, but given that the fairness of the hearing is in question, you can't be surprised that many people choose, unlike you, to believe Rachel Fletcher's denial that she said 'all men are rapists', and not the hearing.
'Curfew on men' is a well-known trope: it was the subject of a play in the 1980s, a TV programme in the 2020s, and an intervention in the House of Lords after the murder of Sarah Everard, which was clarified as being 'a rhetorical device' rather than an actual suggestion.
I don't believe RF was suggesting it as a serious possibility either.
You manage to come up with a handful of cases where men have been advised to take extreme precautions when out a night. The point is that women always have to take a range of extreme precautions which men normally don't.
I would be in agreement with you that if a woman police officer was constantly saying negative things about men that they might find offensive, a superior should have a word along the lines of 'Could you have a think about how those comments are being received by the team? They aren't welcome, so give it a miss, OK?'
Just as I trust the same superior would call in any male police officer who said anything that a woman might find offensive, and issue him with the same suggestion. Are you confident that that happens to sexist male police officers, Walkden? I'm not.
But even accepting your point that a female police officer should be held to the same high standard that male police officers are held [in an ideal world], is what RF is alleged to have said in an informal context, gross misconduct?
Some examples of 'gross misconduct' by male police officers includes sending 'dick pics' to colleagues; engaging in explicit, sexual communications on his MPS mobile device with a member of the public; conducting an emotional & sexual relationship with a vulnerable woman with mental health issues.
Published items | Metropolitan Police
So even allowing for the points you make, Walkden, and agreeing that all police officers, male or female, should be held to a high standard of behaviour, accusing a woman officer of gross misconduct because she may or may not have spoken unacceptable words feels like she's being unfairly picked on.