It's unclear how, or even if, Niemann cheated. The evidence is, at best, circumstantial: a win by a slightly weaker player, playing black, in a line that should have been impossible to prepare for.

So some see him as throwing a tantrum after an unexpected loss, and blaming it (implicitly) on cheating. We can't know if he's right, and we may never actually know. In the absence of confirmation, some people will think less of him for that.

Carlsen is seen as having drawn unwilling participants into his drama (he withdrew from a Swiss style tourney this forfeiting several games), he is seen as passive-aggressive for not making any direct allegations, and there is an arrogance around Magnus believing he knows better than the chess community and organizers about how to deal with former cheaters when they have quite obviously chosen to forgive and trust Hans.

I’m sure some people think Magnus is very brave and courageous for what he’s doing but my general impression is most people don’t approve of Magnus’s methods.

Thank you for explaining!

Okay now that Magnus has made a direct allegation and is telling everybody clearly about how he doesn't want to play with Hans in any future tournaments, everybody loves him again. The negativity you saw towards him I think was purely just that he was being passive aggressive and not talking to anybody and just dropping out of tournaments randomly. It was just a bad way to go about things.

Now you'll see the Magnus hero worship you expected.

He ruined two tournaments in a row, first by withdrawing from the middle of a round robin tournament and second by intentionally throwing a game. If Niemann now ends up qualifying by less than 3 points the guy in 9th will justifiably be extremely upset.

>I would have thought that chess fans would have seen this as a brave and perhaps even virtuous move?

There were many people who defended him withdrawing from Sinquefield but throwing a game is just embarressing, especially in the qualification stage.