I think the difference is that this is an anonymous post about a situation with no names attached. ... an abstract situation that we all understand is from one person's point of view, it's a little different...
Jeremy to speak to what you said first, it really isn't an abstract because it is about real people in a real situation. Tom28, the woman and the sensei and the dojo aren't fictional characters to illustrate something. Being anonymous here isn't going to prevent the dojo or the sensei who Tom28 is, or the woman. It simply means it makes it harder to people to sue if it is anonymous.
As I established, the sensei is a real person and he isn't anonymous to everyone. One poster calls for similar harassment laws in the dojo you see in the work place, and clearly despises him. Another post who makes it know how much the sensei is despised by the poster uses him as the poster child to say all men are pigs. Simply to name a few posters who posted assuming the worst of the sensei. Where is the love?
And it is respected that you give advice, but to whom? Has anyone given advice to the sensei? Because we assume automatically from a narrow, limited, and simple snap judgement perspective she is a victim and he is the victimizer. All based on a third person account. Tom28 is the one that people (some have) should be addressing. But the focus of this thread isn't his issue, but rather looking at the woman as a victim and the sensei as a sexist pig victimizer. The latter shouldn't even be the focus, but it is because people make snap judgements base on what they read with little examination.
If the sensei in question was a well known shihan or someone like Clint George (his Aikido background), people would be going to bat for the unnamed sensei, the same people who are attacking him now. Am no Aikido historian, but wasn't there a well known popular sensei who did hit on all the women and people allowed it to happen by turn a blind eye because he was a famous teacher?
The mindset of people who permit a famous sensei to get away with one thing, and where a lesser known sensei whose actions are from a third party POV can jump to conclusions and hang a person on the net instantly. The latter a big concern with the discussion on Clint George to maintain the innocent until proven guilt. But that is of little concern with an unknown sensei described by a third party in an anonymous thread where it is strongly assumed and played out that the women is the victim and the man is the monster. Being in this forum gives the same people who where concerned about Clint George being accused and an opportunity for a field day of assumptions and twisting of this sensei being a monster victimizing women horribly, a crime against all women where he should be locked up and the key thrown away. Where a mob frenzy can be pitched up to a fever level and this sensei can be an example to all men as he is crucified on the net. Maybe that is the importance of having all of it being anonymous.